In a large baking/casserole dish (seriously a roasting pan is more the size you'll need), lightly spray with a non stick spray and add a few large spoonfuls of sauce to bottom of the dish.
Put 5-6 lasagna noodles over sauce.
Spoon ⅓ of the ricotta cheese on top of noodles and spread evenly.
Place half the shrimp on one half of the noodles and half of the chicken on the other side (so one side is shrimp, the other side is chicken).
Add sliced tomatoes on top of both the shrimp and chicken.
Pour ⅓ of the sauce over shrimp and chicken.
Sprinkle with ⅓ of the mozzarella cheese.
Add another 5-6 lasagna noodles, ricotta cheese, remaining shrimp and chicken.
Pour another ⅓ sauce, add ⅓ of the mozzarella cheese.
Add the remaining noodles and on top of the third layer of noodles, add remaining ricotta cheese, sauce and top with remaining mozzarella cheese.
Spray large piece of foil with a non stick spray and cover lasagna (a tip I learned off The Recipe Critic's post, which I NEVER thought about doing before. What a great idea to keep the cheese from sticking).
Place baking dish on a large cookie sheet to catch any liquid spills.
Cook for 60-70 minutes, then remove foil and cook for an additional 10 minutes or so to brown the cheese a bit.
Remove from oven, let rest for a few before serving.
Enjoy!