For the chorizo and pumpkin filling, heat oven to 450˚F. Arrange the squash on a baking sheet and spray with oil, season with salt, pepper, nutmeg, cinnamon and chili powder. Roast to tender and brown at edges, 25 minutes. Reduce heat to 325˚F.
In a skillet over medium-high heat, brown and crumble the chorizo in olive or vegetable oil, add onion, garlic and peppers, and cook until onions are translucent. Add ½ cup water and let it absorb.
Combine squash with chorizo, and set aside.
For the refried beans, heat olive oil, a turn of the pan, in a small saucepan over medium-high heat. Add onion, garlic, jalapeños, salt, pepper and cumin, and cook 5 minutes to soften. Add water and reduce to 2-3 tablespoons. Add beans and heat through.
Transfer beans to the bowl of a food processor and add lime juice and hot sauce. Process until smooth, and adjust salt to taste.
For the tomatillo salsa, in a food processor, combine tomatillos, jalapeno or serrano, red onion, garlic, agave, cilantro and lime. Pulse to combine.
For the chipotle sour cream, process chipotle in adobo, sour cream, lime, and honey in food processor. Transfer to squeeze bottle.
For the nachos, arrange blue corn tortilla chips on parchment-lined baking sheet or sheets.
Toast chips at mid-level rack 2 minutes, top with even layer of half of both cheeses, toast 2 minutes, add black bean spread on melted cheese to keep chips from getting soggy. In an even layer, add chorizo and roasted pumpkin filling, then top with remaining cheeses and brown. Top with chipotle sour cream and dot with raw tomatillo salsa and pickled jalapeño rings.