In a large skillet, heat oil over medium heat until shimmering and hot. Sprinkle chicken all over with salt and pepper. Add chicken thighs to pan and brown both sides, about 2 to 3 minutes per side.
Using a slotted spoon, transfer thighs to a large 9x13 casserole dish and arrange in a single layer. Sprinkle with artichoke hearts, black olives, and diced tomatoes.
Sprinkle with shredded cheese. Bake 25 to 30 minutes, or until chicken is cooked through. Turn oven to broil and cook another 2 to 3 minutes, to lightly brown cheese on top.