Heat oil in a large pot, add onions, and cook, stirring occasionally, until onions are translucent, about 4 min. Stir in tomatoes and jalapeños, cook, stirring occasionally, about 3 min. Add water and bring to a boil. Remove from heat. Whisk in seasoning packets until thoroughly combined.
Add half of the potatoes to the bottom of a 2.5-in deep, full-size, steamtable pan. Top with pulled pork. Add remaining potatoes. Carefully pour onion mixture over potatoes.
Bake in a convection oven at 350° F, uncovered, until potatoes are tender, about 45 min. Let rest 20 min in a steam table before serving. Serve individual portions topped with shaved cabbage, pico de gallo, and crispy tortilla strips.