Cut the chicken into inch size cubes, place in a gallon size plastic bag along with the minced garlic and 1/4 cup of the teriyaki sauce. Massage the bag until evenly mixed. Marinate in the fridge at least an hour or overnight.

Thinly slice the bell peppers, onion, and mushrooms.

Turn your Blackstone griddle on and set it to medium/ medium high heat. Once preheated, add some oil and the chicken, veggies, and remaining 1/4 cup teriyaki sauce. Season lightly with kosher salt and pepper.

Cook 7 to 9 minutes, flipping and turning a few times throughout using hibachi spatulas. Move the chicken and veggies to one side of the griddle and turn the heat down to medium.

Add more vegetable oil to the empty space of the griddle and place the tortillas flat.

Place two slices of the of the cheese on one side of each tortilla, then use the spatulas to put some chicken and veggies over the cheese, add two more slices of cheese over the chicken and veggies. Use the spatulas to fold the empty side of the tortillas over the filling.

Flip the quesadillas and remove from the griddle once the cheese is melted and tortillas are cooked to your liking. Serve with yum yum sauce for dipping if desired.