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You're basically making the sauce here in bulk and poaching the first meal's worth of protein with it. How much you get out of it depends on how much you put in, but 3-4 meals of sauce and 2 meals for two's worth of protein from a pork loin (for example) is typical.
It hinges on whether you have tomatillos or not, which makes it convenient to pull together off a single realization in the vegetable aisle.
Into a crockpot goes:
Nestle a meal or two's worth of lean protein (1-2 lb pork loin or chicken) in with the vegetables and crockpot til the protein is fork-shreddable (4-6 hours).
Remove protein. Stick-blend crockpot contents into a sauce. Shred protein and add enough sauce (but not too much) for it to pull together. Salt to taste.
Heat a pan to medium. Add a few inches of water to a bowl with a few tablespoons of oil. Submerge a corn tortilla quickly in the water, allow excess liquid to run off, and add to pan. It will sizzle; flip 15-30 seconds after the sizzling stops, heat 10-15 more seconds on the other side, and remove to a paper towel folded in half over it. Repeat 2x per taco.
Protein + extra sauce + cotija + minced onion + cilantro + lime, with leftovers for days.