Mix the chili powder, cumin, coriander, paprika and cinnamon in a small bowl. Put the beef in a medium bowl; add 4 teaspoons of the spice mixture, season generously with salt and pepper and toss until coated. Set aside.
Set an Instant Pot to saute at normal heat. When the display indicates ?hot,? add the olive oil, then add the onion, poblano, garlic and a generous pinch of salt. Cook, stirring often, until tender and lightly browned, about 5 minutes. Stir in the remaining spice mixture and cook, stirring, until lightly toasted, about 1 more minute.
Cancel the saute setting and stir in 3/4 cup water and the tomatoes, scraping up any browned bits from the bottom of the pot with a wooden spoon. Add the beef and nestle it in the liquid. Put on the lid, making sure the steam valve is in the sealing position, and set the cooker to high pressure for 30 minutes. Let stand 10 to 15 minutes, then carefully turn the steam valve to the venting position to release the remaining pressure.
Turn off the cooker. Remove the lid and stir in the crushed corn chips, gently breaking up any large chunks of beef. Let cool a few minutes, then spoon off any excess fat from the top. Stir in the vinegar and cilantro; season with salt and pepper. Serve the stew over rice; top with cheese, scallions, cilantro and more corn chips.
Photograph by Ryan Dausch