Season the chicken with all-purpose seasoning and place into the bottom of the Instant Pot. Pour in the chicken broth. Press "poultry". It should automatically start for 15 minutes on the timer.
Meanwhile, sautee the mushrooms over medium heat in a small skillet with a little cooking spray. Remove when the mushrooms have cooked through.
Microwave the spinach according to package instructions, then drain and press out the water.
When the chicken is done, use a fork and knife to shred the chicken.
Turn on your quesadilla maker or heat a large skillet over medium heat. When ready, build your quesadilla: tortilla, chicken, mushrooms, spinach, cheese, and top with another tortilla. Cook until crisp and golden brown on each side. Serve with a giant dollop of sour cream.