Preheat oven 400°.Heat oil in skillet over medium-high; add beef and onion and cook stirring often until beef is no longer pink and onion is tender 7 to 8 minutes.Drain fat and place over medium.

Add paste to beef stirring often 1 minute.Sprinkle beef with flour and cook stirring constantly 1 minute.Add broth stirring constantly until mixture thickens 3 to 4 minutes.Stir in diced tomatoes and chiles,mustard,Worcestershire sauce,salt,pepper,stirring often 2 minutes.Stir in 1/2 cup each of Monterey Jack cheese and Cheddar cheese and cook stirring until cheeses melt 1 to 2 minutes.Spoon mixture into a greased 11- x 7-inch baking dish.Top evenly with tater tots.Place dish on baking sheet.

Bake uncovered until bubbly around edges and potatoes are golden brown 30 to 35 minutes.Sprinkle top with remaining 1/2 cup each of Monterey Jack and Cheddar cheese and bake until cheese is melted 3 more minutes.Remove from oven let stand 10 minutes.Sprinkle casserole with bacon and chives. You can sprinkle chopped lettuce and tomato on top. Drizzle with ketchup Or mix up 1/2 cup of sour cream,1/2 cup mayonnaise and 1/4 cup of Sriracha stir & drizzle on top.