In a large skillet with high edges, heat 2 tbs of butter over medium-high heat, swirling to coat the bottom of the pan. Season the chicken with the salt and pepper and place in the pan. Sear the chicken until golden brown, about 3 minutes on each side. Remove the chicken from the pan and set aside.

With the same pan on medium high heat, add onions, and peppers and saute for 2-3 minutes, until the onion becomes translucent. Add the mushrooms and continue to cook, stirring for 2 minute. Add the garlic and stir until aromatic, about 1 minute. Add the diced tomatoes.

Return the chicken to the pan and cover everything with the chicken broth. Reduce the heat to medium and bring everything to a simmer. Turn the heat down to low and continue to simmer (not boil) until the chicken reaches an internal temperature of 160 degrees, about 30 minutes.

Garnish with chopped basil and serve.