Using Sonar Platinum, I’m trying to create an audio track that tells a story about animals using musical instruments. Is there a way to change the track’s voice so that it sounds like a chipmunk? 

Hi, and welcome to this forum. You could try using Melodyne for this.
I suggest recording the vocals as near to pitch as you can (high instead of low). 
Select the notes, and drag to preferred note.
I also suggest doing this in small(ish) parts, not long passages.
Others may know better.
All the best.

jacorrea
Using Sonar Platinum, I’m trying to create an audio track that tells a story about animals using musical instruments. Is there a way to change the track’s voice so that it sounds like a chipmunk? 

Melodyne has a Format control that allows you to adjust the size of the voice box, when used in conjunction with Pitch you can get really cool sound effects for low voices or really high chipmunk type effects.
 
I found one older video that will you give an example of what the Format control does in Melodyne.
https://youtu.be/Kaqrlh7V-J0
 
The UI has changed a little bit over the years with Melodyne but the workflow is basically the same. Good luck!

Thank you very much for your help, gentlemen.

You can also use the Process > Transpose > Transpose Audio function.