Combine Italian seasoning, chopped thyme, garlic powder, and lemon pepper. Season chicken with half of the mixture. Add olive oil to the heated skillet and add chicken. Cook chicken in a skillet over medium heat 5-7 minutes on each side until lightly browned and cooked through. Transfer chicken to a plate and cover to keep warm.
Add mushrooms to pan and stir over medium heat until mushrooms are tender, about 5 minutes. Add garlic and sprinkle in lemon zest and lemon juice and stir. Add flour and remaining herbs and stir until the flour is absorbed. Add half and half and the chicken stock. Stir as the mixture heats and thickens.
Return chicken to pan (I like to slice the chicken into strips) and toss in the sauce to coat. Sprinkle with salt and pepper to taste.