Heat 2 Tbs. of the oil in a 5- to 6-quart heavy-duty pot over medium-high heat until shimmering hot, about 2 minutes. Add the garlic and onion, season with 1 tsp. salt, and cook, stirring occasionally, until the onion begins to soften, 3 to 5 minutes. Stir in the paprika, chili powder, and cumin, cook for 1 minute, and then add the tomatoes and their juice. Stir, smashing the tomatoes against the side of the pot to break them up slightly. Add 2 cups water and bring to a simmer. Stir in the chickpeas, corn, bell pepper, jalapeño, and 1 Tbs. salt and cook until the peppers have lost their raw crunch, 8 to 12 minutes (at this point, if the chili looks too thick, add an additional 1 cup of water).
While the vegetables cook, heat the remaining 1 Tbs. olive oil in an 10-inch skillet over medium-high heat. Add the almonds and cook, stirring constantly, until goldenbrown, 2 to 3 minutes. Using a slotted spoon, transfer them to a plate lined with paper towels and immediately season them with 1/2 tsp. salt.
Stir the basil and scallions into the chili. Serve the chili with a dollop of sour cream (if using), more scallions, and the almonds.
You can make the chili up to four days ahead; store it in an airtight container in the refrigerator. Reheat gently to serve.
Serve with basmati rice.