Preheat oven to 350°F.
Heat the chili in a small sauce pot over medium heat until steam escapes when you take a spoonful and hold it up. Drain off as much grease as possible. Set aside to cool a bit while you prepare the rest of the ingredients. (If using frozen, cooking according to package directions, then drain off any grease that rises to the surface. Set aside to cool.)
In a medium bowl, mix the cream cheese with the half of the tomatoes and chiles, plus the onions until well-combined. Add more tomatoes and chiles, if desired. Spread into an 8"x8" oven safe pan (an offset spatula works great here).
Pour the chili evenly over the cream cheese mixture. Top with the grated cheese, plus the optional garnishes.
Bake for 10 to 15 minutes, until the grated cheese is melted.
Serve warm with corn chips on the side.