Can I apply for unemployment benefits while awaiting a decision from workers compensation claims?

If your position with an employer has been terminated and you no longer have a job to go back to, there is nothing legally preventing you from making such an application for such benefits if you suffered an on the job injury and are currently receiving worker's compensation benefits.

You can certainly try to apply and explain what is occurring. The decision may not be immediate and so you would have to figure out what next to do. If you have an attorney representing you in the workers compensation matter, you should consult with him or her in order to determine if this is the best route for you.  Of course, the severity of your injury will determine if unemployment or other sources (disability) would be your best route.