Pat the chicken dry with a paper towel, season with salt and black pepper, and set aside.

Heat olive oil in a skillet over medium-high heat; cook chicken for 5-7 minutes per side until golden brown and cooked through. Remove chicken and set aside.

In the same skillet, add chopped onion and sauté for about 5 minutes until translucent.

Add minced garlic and cook for an additional minute until fragrant.

Deglaze the skillet with pepperoncini juice, add chopped pepperoncini, chicken broth, Italian seasoning, and red pepper flakes. Simmer for 5 minutes.

Stir in heavy cream and return chicken to skillet. Simmer until sauce thickens, about 5 minutes.

Adjust seasoning if necessary and garnish with parsley. Serve over cooked pasta or rice.