Preheat the grill, pellet grill, smoker, or oven to 425°F. If using a charcoal or gas grill, establish an indirect cooking zone.
Scrub the potatoes clean and dry them thoroughly. Pierce each potato several times with a fork.
Rub the potatoes lightly with about 1 tablespoon of olive oil and season the outsides with approximately 1/2 teaspoon kosher salt.
Place the potatoes over indirect heat or on a baking sheet in the oven. Cook until completely tender when pierced with a knife, approximately 45–60 minutes depending on potato size.
While the potatoes cook, prepare the chorizo. Place a cast iron skillet or saucepan over medium heat and add the fresh chorizo.
Cook the chorizo, breaking it into small crumbles, until browned and fully cooked to at least 160°F, approximately 7–10 minutes.
Transfer the cooked chorizo to a paper towel-lined plate using a slotted spoon. Leave approximately 1 teaspoon of rendered fat in the pan and discard excess if necessary.
Add the diced jalapeño and white portions of the scallions to the skillet. Cook for 1–2 minutes, just until slightly softened.
Pour in the lager and stir while scraping any browned chorizo bits from the bottom of the skillet. Bring the beer to a gentle simmer.
In a bowl, toss the shredded cheddar and Monterey Jack with the cornstarch until evenly coated.
Reduce the skillet to low heat. Add the cheese mixture a handful at a time, stirring continuously and allowing each addition to melt before adding more.
Stir in the garlic powder and approximately half of the cooked chorizo. Keep the queso warm over very low heat. If it becomes too thick, stir in a splash of beer or milk.
When the potatoes are tender, remove them from the cooker and allow them to cool for approximately 10 minutes, or until they can be safely handled.
Cut each potato in half lengthwise.
Scoop out the centers, leaving approximately 1/4 inch of potato attached to the skin around the sides and bottom.
Increase or adjust the cooker to approximately 400°F if necessary.
Brush the inside and outside of each potato shell lightly with the remaining olive oil. Season the inside surfaces lightly with the remaining kosher salt.
Arrange the potato shells skin-side up on a baking sheet or grill-safe tray. Cook for approximately 8 minutes.
Flip the shells cut-side up and cook another 6–8 minutes, until the edges and interiors are lightly browned and crisp.
Spoon approximately 1 1/2–2 tablespoons of warm chorizo queso into each crispy potato skin. Do not completely overfill the shells.
Sprinkle the remaining browned chorizo over the queso.
Return the filled potato skins to the 400°F cooker for approximately 4–6 minutes, just until everything is hot and the queso is bubbling around the edges.
Remove the potato skins from the heat.
Top each skin with a small spoonful of well-drained pico de gallo, sliced scallion greens, and chopped cilantro.
Add sliced or pickled jalapeños and a small amount of sour cream if desired.
Serve immediately while the potato shells are still crisp and the queso is hot.