- Preheat oven to 350°F.
- Layer tortilla chips in a 13"x9"x2" baking dish.
- Blend cheeses.
- Sprinkle half of the cheese mixture and tomatoes over tortilla chips.
- Melt butter in large frying pan over medium heat.
- Add garlic and onion to pan and sauté until onions are tender, approximately two minutes.
- Add shrimp and lobster meat and heat until warm, about three minutes.
- Drain and layer warm seafood mixture on top of nachos.
- Top with the remaining cheese and bake at 350°F for about 15 minutes until cheese is melted.
- Top with scallions and dollops of sour cream.
- Serve hot with salsa on the side.