In a small bowl combine the brown sugar, paprika, garlic powder, onion powder, salt, pepper, cumin, mustard powder, and cayenne pepper.
Rub the mixture all over the chicken breasts.
Put 2 cups of BBQ sauce and chicken broth in the bottom of an Instant Pot and mix.
Add the chicken breasts on top of the sauce.
Close the lid and set the Instant Pot on high pressure for 15 minutes.
Naturally release for 10 minutes then manually release the rest.
Remove the chicken from the Instant Pot and shred.
Return the chicken to the Instant Pot and add additional BBQ sauce. Mix until well combined and saucy.
Put on slider buns and enjoy!