In large skillet, cook onion and pepper in butter until tender. Stir in chili, corn and olives, bring to boil. Add cheese and stir to melt. Pour into baking pan. Prepare muffin mix according to package directions. Spoon dough in diagonal bands across top of casserole. Bake at 400° for 15-20 minutes.
This one seems very much like a tamale pie, although named differently. Note how no additional spices, even salt and pepper, are required ... I guess that's what makes it "jiffy" cooking.