Can I get a sliding genioplasty if I have fillers in my chin?

One issue with having filler in your chin prior to having sliding genioplasty is that your surgeon will have difficulty know what your true baseline chin appearance is. Ideally you would have the filler dissolved prior to surgery.

It is in your best interest to have the fillers dissolved prior to sliding genioplasty surgery, in order for a surgeon to best assess the position of your jawline prior to surgical intervention. 
Be sure to trust your face to a specialist and best of luck to you!