First, make the salsa verde. Preheat the broiler on high. Place the tomatillos and jalapeños (if using) on a rimmed baking sheet or broiler tray. Drizzle with olive oil, rub to coat, and season with salt and pepper. Place in the broiler and let roast for about 10-15 minutes, turning with tongs halfway, until blackened in spots. The longer you let them roast, the smokier your salsa will be.
When the tomatillos and jalapeños are done roasting, place them in a blender. Add the yellow onion and cilantro, and blend until the salsa is smooth (you don’t want large chunks of onion or strings of cilantro). Season with a generous sprinkle of salt and stir in the juice of 1 lime. Set aside for now.
Next, add 1 tablespoon of olive oil to a large nonstick skillet and warm over medium-high heat until shimmering. Add the bell pepper slices & red onion, sprinkle with a little salt and pepper, and sauté, stirring occasionally, until the vegetables are softened and blackened a bit, about 10-15 minutes. Remove to a plate and set aside.
Add another tablespoon or so of oil to the pan. Season the chicken strips with salt and pepper, and add to the skillet. Cook for about 10 minutes, or until lightly browned, stirring occasionally.
When the chicken is browned, add 1 cup of salsa verde to the pan and cook for about 5 minutes, until the salsa has turned a darker green color and most of the liquid has evaporated, creating a nice coating on the chicken.
When you’re ready to eat, take a flour tortilla, fill it with chicken strips, sauteed veggies, sour cream, fresh lime juice, sliced radishes, and salsa verde. Add a dash of hot sauce if you like things spicy. Fold up and enjoy.