Hi Sonar experts. I'm still learning all the tools in Sonar and am trying to help a friend. He has an acoustic guitar track that has about 1-2 beats of what sounds like a slight buzz. What tool would you recommend to minimize this buzz on top of the acoustic. I have isolated it by splitting the track and assumes maybe some form of EQ or limiter might be the best solution but wanted to reach out to hose better than me before trying. Is there a Sonar tool you would reach out for to handle this? Thanks in advance for your support.

It may sound like a lame answer but I assure you it's honest - overdubbing.

Sorry to not be suggesting a cheap solution.  (Yeah...there's the overdub idea.)
 
However...I'd strongly suggest getting iZotope RX in your toolbox.  You'll want the Standard edition, because it includes Spectral Repair.  The De-hum thing that's included in the economy "Elements" version is just a notch filter arrangement that works a lot more poorly than you would hope...even though it seems to be the "correct" tool.
 
I know you are probably just trying to solve this one problem...right now...and just once.  Consider though that you'll also encounter similar (or worse) problems down the road if you spend any significant time and energy in recording.
 
I'm just sayin...
 
On the other hand...if the hum is low enough that it's masked when the guitar is actually playing, you could try using a gate set to close when the guitar gets out of the way.  I think there's at least two of these included with SONAR.
 
The problem with using EQ as a solution...particularly when your ground hum presents itself as a "buzz"...is that you need to notch out all the harmonics as well as the 60 Hz fundamental frequency.  That ends up doing significant damage to the signal you are trying to keep.  Besides...it just doesn't work all that well in my experience.

dantarbill
However...I'd strongly suggest getting iZotope RX in your toolbox.  You'll want the Standard edition, because it includes Spectral Repair.

  Ill second that.
 
If the hum is isolated from the music... just chop it out.  Or use a gate.  If its consistent with the entire track.... well... 

Well this is not lossless, but it can be very successful. I have had excellent results with scratched records, tape hiss etc. It will require that some section of the track had only the hum, even if it also impinges over the actual playing. It can be a very short piece of sample, but has to be ONLY what you want to remove. Just realise that it will take away anything that matches the profile of the noise, including some music.
 
Download Audacity, then load up a wav _COPY_ of your track, use Effects, Noise Removal. You "teach" it what is noise, then ask to remove it from the whole track or wherever it is a problem. So you select a place where only noise is, then (weirdly) ask to reduce noise, the Get Profile, then select the entire place you want to reduce noise in, open Effect / Noise Reduction again and set the parameters of reduction amount etc. It will take a few goes, maybe, to get the right settings to make the noise negligible, without affecting the guitar.

What's not clear from the OP is this a background type noise or a String buzz?? 
Like is it though the whole track or just a few beats like you say. 
 
If it's just a fret/string buzz then one solution is find a place in the song where the same chord/ phase etc was played and copy paste it over the bad part. Always make a back up first. 
Or as said replay the part using a lane or parallel track and paste it in. Even if you use a different guitar and/ or player it can work. 
 

What I would do is download the trial version of Meldaproduction MSpectralDynamics.  The 30 day fully functional trial should be long enough to perform a spectral removal of the buzz. 

Another noteworthy addition here is that currently, this particular plugin is on their list of plugins that is available for 50% off.

http://www.meldaproduction.com/MSpectralDynamics

I'll add a vote for RX, I love that. But I assumed it was string buzz and I think it would be hard to get an edit like that to sound completely natural. String buzz isn't just the presence of buzz but also the absence of overtones you do want.

as noted before (dantarbill) many times to remove 60hz you need to remove the harmonics, however, sometimes it's just one or two of the harmonics which are actually problematic so notching those out could be effective. also, most times, the video monitor can cause noise like hum but at different than line power frequency...
 
Sound Forge has a decent noise reduction plugin which (like the audacity example - oldnick) is trained.  best bet per the first response (sanderxpander) - overdub :-) second might be convert the guitar part to midi and use an virtual instrument to re-create it (which can lead to interesting things like alternative guitars, synths etc)

There is a de-essing technique to gate and then reverse phase of track over to another track, and then blend these. By adjusting volume of second gated track you can get the desired effect - cancelling unwanted parts.
 
But it is built on ability to extract the buzz stuff first with the gating.
 
It can work without any super-duper tools....but a regular de-esser can work too.