Start by bringing a large pot of salted water to a boil and adding the chicken breasts. Simmer for 25-30 minutes until the internal temperature reaches 165°F. While the chicken cooks, dice the onion finely, seed and dice the jalapeños, mince the garlic, drain the spinach very thoroughly (pressing it in a colander or squeezing it in a clean kitchen towel to remove excess moisture), and have the cream cheese softened on the counter. Once the chicken is cooked through, remove it from the water and let it cool slightly before shredding it with two forks into bite-sized pieces.

Melt the butter in a large skillet over medium heat. Add the diced onion and jalapeños, cooking for 5-7 minutes until softened and fragrant, stirring occasionally. Stir in the ground cumin, smoked paprika, and onion powder, cooking for 30 seconds to toast the spices and deepen their flavor—this step is crucial for building complex flavor. Add the minced garlic and cook for another 30 seconds until aromatic, being careful not to burn it.

Stir the cream of chicken soup and lime juice into the aromatic base until smooth. Reduce heat to low and stir in the softened cream cheese, stirring constantly until fully incorporated and the mixture is creamy. Add the shredded chicken from Step 1 and the well-drained spinach, folding gently until everything is evenly distributed. The mixture should be creamy but not soupy; if it seems too wet, you can simmer it for 2-3 minutes. I like to taste the mixture at this point and add a pinch of salt if needed—the lime juice brightens everything beautifully.

Preheat your oven to 350°F. Crush the corn chips into bite-sized pieces (not too fine, as they should maintain some texture). Spread a thin layer of the chicken-spinach mixture from Step 3 on the bottom of a 9x13 inch baking dish or similar size. Sprinkle with crushed chips, then add a generous handful of shredded cheddar jack cheese. Repeat the layers (mixture, chips, cheese) until the dish is nearly full, then finish with a final layer of crushed chips topped with the remaining cheese. I find that 3-4 layers works best for even cooking and texture throughout.

Bake uncovered at 350°F for 15-20 minutes, until the cheese is melted and bubbly around the edges and the top is golden. The casserole doesn't need to bake long since all the components are already cooked. Let it rest for 5 minutes before serving—this allows the casserole to set slightly and makes it easier to portion.