Place the beef and carrots in the Instant Pot and set to sear.
While beef is searing, place the masa harina and oil in a small saucepan and cook over low heat, stirring constantly, until mixture browns moderately (color of peanut butter); set aside to cool.
Add remaining chili ingredients plus the roux to the beef and stir.
Turn Instant Pot from Sear to OFF.
Place the lid on the Instant Pot and set to the locked position, and make sure the valve is CLOSED.
Turn Instant Pot on and set to MANUAL for 15 minutes.
When it beeps and goes to warm, turn the Instant Pot OFF and using the handle of a wooden spoon, tap the valve open.
Allow steam to release completely before removing the lid.
Stir the chili and set to sear again, stirring frequently until it is very thick.
While chili cooks, divide the remaining beef into twelve pieces and shape into small slider patties.
Season with salt and black pepper.
Pan fry the patties until cooked through or as you like them.
Place cheese on cooked patties and melt in the microwave if you need to.
Assemble sliders on split Hawaiian rolls topped with either one or two patties, and chili on top of the patties, with whatever other toppings you like (such as onion).