Heat the extra virgin olive oil in a large deep skillet over medium-high heat.
Add the ground chicken and finely diced yellow onion to the skillet, breaking the meat into small crumbles with a wooden spoon.
Sauté the mixture for 8 to 10 minutes until the chicken is thoroughly browned and the onions are translucent.
Stir in the minced garlic, dried oregano, sea salt, and black pepper, cooking for 1 minute until highly fragrant.
Pour the marinara sauce and water into the skillet, stirring to combine with the meat mixture.
Break the whole wheat lasagna noodles by hand into 2-inch pieces and press them down into the sauce until they are fully submerged.
Reduce the heat to low, cover the skillet with a tight-fitting lid, and simmer for 15 to 20 minutes, stirring once halfway through to ensure noodles do not stick to the bottom.
Once the noodles are tender, remove the lid and stir in the fresh spinach, folding it gently until it is completely wilted.
Dollop the part-skim ricotta cheese evenly across the surface of the skillet.
Sprinkle the shredded mozzarella cheese over the top and cover for an additional 2 to 3 minutes until the cheese is melted and bubbly.
Remove from heat and let the lasagna rest for 5 minutes to set before garnishing with torn fresh basil and serving.