Heat oil in a large skillet over medium-high heat. Add onion and cook, stirring constantly, about 1 minute. Add ground beef and cook, stirring, until browned and crumbly, about 5 to 7 minutes. Stir in taco seasoning and cook for another 1 minute. Mix in tomatoes and reduce heat to medium-low.

Cook, stirring constantly, until mixture comes to a simmer. Cook for 3 minutes and reduce heat to low. Add American cheese and stir until melted and fully combined. Remove from heat and let cool.

Preheat the oven to 350 degrees F (175 degrees C). Grease 2 12-cup muffin tins.

Roll out biscuits, 1 at a time, into 4-inch circles. Spoon about 1 tablespoon of filling onto the center of each circle.

Bring dough up around the filling, pinching it together to seal the bottom until the filling is fully encased. Place each biscuit bomb seam side down into the prepared muffin tins.

Brush each biscuit bomb with melted butter and sprinkle with taco seasoning.

Bake in the oven, rotating once halfway, until deep golden brown, about 20 to 25 minutes.