1) Roast for deeper flavor
Heat oven to 450°F. Spread tomatillos, onion, garlic, and jalapeño on a sheet pan. Roast for 12 to 18 minutes until softened and blistered, with a few dark spots. If your tomatillos refuse to char, broil for 1 to 2 minutes at the end (watch closely).
2) Blend the sauce
Add roasted veggies to a blender with cilantro, broth, lime juice, cumin, and salt. Blend until smooth. Taste. If it is aggressively tangy, add 1 teaspoon honey, blend again, and taste.
Sauce yield: You are looking at about 3 to 4 cups of sauce, depending on how juicy your tomatillos are.
3) Toast the cumin, then simmer
Heat 1 tablespoon olive oil in a saucepan over medium heat. Add the ground cumin and stir for 15 to 30 seconds until it smells toasty. Carefully pour in the blended sauce. Simmer 5 minutes to mellow the raw edge and bring everything together. Taste again for salt and lime.
4) Prep filling and pan
Reduce oven temperature to 400°F. Ladle about 1/2 cup sauce into a 9x13-inch baking dish and spread it around.
Toss shredded chicken with 1/2 cup sauce and 1 cup shredded cheese. This is the moisture insurance policy.
5) Warm tortillas so they roll without drama
Quick method: Wrap tortillas in damp paper towels and microwave 30 to 45 seconds.
Extra tasty method: Heat a skillet over medium heat and add a thin slick of oil once (add a touch more only if the pan looks dry). Warm tortillas 10 seconds per side, just until flexible.
6) Assemble
Working one tortilla at a time, add a small handful of chicken filling, roll snugly, and place seam-side down in the dish. Repeat until the pan is full.
7) Sauce and cheese
Pour remaining sauce over the top. If you want a looser, extra-saucy pour, thin the sauce with 2 to 6 tablespoons broth.
Top with the remaining cheese (aim for 1 1/2 to 2 cups on top for good coverage).
8) Bake
Cover with foil and bake 15 minutes. Uncover and bake 8 to 10 minutes more, until bubbly and the edges are starting to crisp.
9) Finish like a pro
Rest 5 minutes. Top with cilantro, red onion, and a squeeze of fresh lime. Serve with sour cream if you want that cool, creamy contrast.