Place the pork chops into a resealable plastic bag set in a bowl. In a blender, combine the pineapple chunks with their juice, guajillo powder, New Mexico chili powder, chipotle, cinnamon, salt, white vinegar, garlic, and green onions. Blend until smooth. Pour the marinade over the pork chops, ensuring they are evenly coated. Squeeze out excess air, seal the bag, and refrigerate for 12 to 48 hours.

Preheat your oven to 325°F (165°C).

Heat olive oil in an oven-safe pan over medium-high heat. Remove the pork chops from the marinade, scraping off any excess, and reserve the marinade for later use. Sear the chops on both sides for about 3 minutes each until lightly browned. Transfer them to a plate and set aside.

Add the sliced onion, cumin, and oregano to the pan. Cook for 1 minute, stirring to combine. If the pan appears dry, add a little more oil.

Turn off the heat and pour in the water or chicken broth. Scrape the bottom of the pan to deglaze, incorporating any browned bits. Place the seared chops over the onion mixture.

Roast in the preheated oven, basting the chops occasionally with pan juices, until they reach an internal temperature of 140–145°F (60–63°C), approximately 20 to 30 minutes. Use an instant-read thermometer for accuracy.

While the chops roast, transfer the reserved marinade to a saucepan. Add water to achieve the desired consistency, then simmer over medium-high heat, whisking occasionally. Adjust seasoning to taste and keep warm.

For the salsa, combine the diced onion, pineapple, oregano, salt, and lime juice in a bowl. Mix thoroughly and garnish with cayenne pepper if desired.

Remove the pork chops from the oven and let them rest, tented with foil, for 5 to 10 minutes. Before serving, drizzle with the warm sauce and add a spoonful of pineapple salsa on top.