Step 1

Rinse chicken thighs and pat dry with paper towels. Heat oil in the pot of an electric pressure cooker (such as Instant Pot®) on "Saute" mode; add chicken. Cook until browned, about 6 minutes per side. Transfer chicken to a plate, reserving drippings in the pot.

Step 2

Place celery, onion, and mushrooms in the pot; cook and stir until soft, about 5 minutes. Add garlic; cook until fragrant, about 2 minutes. Place chicken back in the pot; add tomatoes and tomato paste. Sprinkle with herbes de Provence. Top with water and bouillon.

Step 3

Close and lock the lid. Select high pressure according to manufacturer's instructions. Allow 10 to 15 minutes for pressure to build. Cook for 11 minutes.

Step 4

Release pressure carefully using the quick-release method according to manufacturer's instructions, about 5 minutes. Unlock and remove lid carefully, turning it away from you. Test chicken for doneness; an instant-read thermometer inserted near the bone should read 165 degrees F (74 degrees C). Season the chicken to taste with red pepper flakes and black pepper.