Preheat oven to 400 degrees. On a rimmed baking sheet, toss squash with 1 tablespoon oil and arrange in a single layer. Sprinkle with chili powder and season with salt and pepper. Bake until soft and lightly golden, 20 to 25 minutes.
Whisk together lime juice, cilantro, honey, and remaining 3 tablespoons oil; season with salt and pepper. Arrange romaine on a platter, then top with squash, pepitas, and Cotija; drizzle with dressing.