Heat the olive oil in a pot over medium-low heat. Add the onions, garlic and a big pinch of salt and pepper. Cook, stirring often, until the onions soften, about 5 minutes.: As the olive oil warms you should notice a faint shimmer across the surface and a gentle aroma. The goal is a moderate heat so the onion softens without browning too quickly. Use a heavy bottom pot to distribute heat evenly. A common mistake is turning the heat too high which causes the onion to brown before it has a chance to mellow; if that happens lower the heat and stir more frequently.
Add in the chicken, cumin, smoked paprika and garlic powder. Stir and cook for another 2 to 3 minutes.: When the onion hits the oil it will sizzle softly; the sound will become more subdued as the pieces release moisture. The minced garlic will start to perfume the pan almost immediately, so keep it moving to avoid burning. This stage builds sweetness, and if you overcook the garlic it will taste bitter, so watch for a translucent sheen on the onion .
Add in the stock, crushed tomatoes, black beans and diced green chiles. Bring the mixture to a boil, then reduce to a simmer. Cover and simmer for 15 to 20 minutes.: Expect the onion to go from opaque to glossy and tender, and the kitchen will smell rounded and savory. Stirring prevents sticking and encourages even softening. If your pan seems dry, add a splash of stock; a frequent error is letting the aromatics brown unevenly, which creates hard to mask bitter spots.
Stir in the sour cream. Stir until it all melts in. Taste and season with more salt and pepper if needed.: The moment you add the shredded chicken and spices the aroma will deepen, with smoky and earthy notes unfolding. Toss the chicken so it picks up spice and warms through. This step flavors the meat; under seasoning here leads to blandness later, so be generous but balanced.
Serve with cheddar cheese, tortilla chips, cilantro, green onions and more sour cream.: You'll hear a faint sizzle as the spices toast slightly and the chicken heats. Toasting the spices briefly intensifies their fragrance, but avoid letting them burn, which leads to an acrid taste. If the mixture looks dry, add a touch of stock; not doing so is a common oversight that leaves the pot sticking.
Add in the stock, crushed tomatoes, black beans and diced green chiles: When the chicken stock and crushed tomatoes join the pot the aroma shifts to a bright, tomato forward scent with warming spice. The black beans and diced green chiles add texture and an additional flavor layer. Stir to combine so the beans are evenly distributed; failing to rinse canned beans can leave a metallic or canned taste, so rinsing is important.
Bring the mixture to a boil, then reduce to a simmer: You should see gentle bubbles rising when it boils, and then smaller, steady bubbles at a simmer. Reducing to a simmer allows flavors to meld without evaporating too much liquid. Rapid boiling can toughen proteins and reduce liquid too quickly, so lower the heat until the surface is just rippling.
Cover and simmer for 15 to 20 minutes: During the simmer the stew will deepen in color and the aroma will concentrate, with the tomatoes and spices melding. This resting period softens flavors and lets the black beans absorb the broth. Avoid lifting the lid constantly, as that releases heat and prolongs cooking time; check only once or twice toward the end.
Stir in the sour cream: As you fold in the sour cream the chili will take on a creamier sheen and a slightly tangy finish that cuts through acidity. Stir until fully incorporated so the texture becomes silky. Adding it off heat is safer to prevent curdling; if you add it to a raging boil it may split.
Stir until it all melts in: You will notice the chili mellow as the sour cream integrates, with a smoother mouthfeel and softened edges to the spices. Taste now and adjust seasoning. A typical mistake is neglecting a final seasoning check, which can leave the dish under salted.
Taste and season with more salt and pepper if needed: This is the finishing calibration where small adjustments make a big difference. Use a teaspoon at a time, tasting after each addition, to reach balance. Over salting is hard to reverse, so add cautiously.
Serve with cheddar cheese, tortilla chips, cilantro, green onions and more sour cream: The finishing garnishes add texture contrast and brightness; warm chili will melt the shredded cheddar cheese , and the crisp tortilla chips create delightful bites. Scatter chopped cilantro and sliced green onions for freshness, and offer extra sour cream for creaminess. A common serving mistake is adding cold toppings too early, which can cool the bowl quickly, so garnish just before plating.