Bring a large pot of salted water to a boil. Wash and dry all produce. Core, deseed, and dice poblano into 1/2-inch pieces. Trim and thinly slice scallions, separating whites from greens. Thinly slice garlic. Finely chop tomato.

Pat chicken dry with paper towels. Place in a large bowl with a large drizzle of olive oil, Blackening Spice, and a few big pinches of salt; toss to coat.

Once water boils, add pasta to pot. Cook until al dente, 9-11 minutes. Scoop out and reserve 1/2 cup pasta cooking water (1 cup for 4 servings), then drain and set aside.

Meanwhile, heat a drizzle of olive oil in a large pan over medium-high heat. Add poblano and a pinch of salt. Cook, without disturbing, until poblano begins to char, about 3 minutes. Add chicken and cook, stirring occasionally, until browned and cooked through, about 5 minutes. Stir in scallion whites and garlic. Cook until fragrant, about 1 minute. Stir in half the tomato and a pinch of salt.

Reduce heat under pan to medium low. Add cream cheese and 1/3 cup pasta cooking water (2/3 cup for 4 servings); stir until thoroughly combined. Stir in pasta and cook, stirring, until well-combined, 1-2 minutes. Turn off heat. Stir in cheese, stock concentrate, half the hot sauce (or as much as you like), and 2 TBSP butter (3 TBSP for 4). Stir until butter melts and sauce is smooth. (TIP: Add more pasta water if sauce seems dry.) Season with salt and pepper.

Divide pasta between bowls or plates. Garnish with scallion greens and remaining tomato. Drizzle with any remaining hot sauce, if desired.