Place sliced onions in the bottom of the Instant Pot.
Place chicken breasts on top of the onions.
In a small bowl, mix together brown sugar, salt, black pepper, smoked paprika, garlic powder, and onion powder. Sprinkle on top of chicken.
Pour the chicken broth on the side of the chicken (try to not wash off any of the seasonings you just topped with chicken with.
Pour 1 cup of the BBQ sauce on top of the chicken.
Place the lid on the Instant Pot, press the MANUAL (or PRESSURE COOK) button and set the timer for 20 minutes.
When the timer is done, let the pressure do a NATURAL RELEASE for 5 minutes. Then move the valve from sealing to VENTING and let the rest of the pressure release.
Remove chicken from Instant Pot and shred using 2 forks (it should fall apart fairly easily). Place shredded chicken back in the Instant Pot with all the juices and stir together.
Serve over hamburger buns and enjoy.
Notes
Avoid washing the seasonings off of the chicken breast when pouring the chicken broth.If you want to try it out, take a look at this 40-minute hamburger buns recipe from Taste of Home and taste the difference for yourself!