Bring a large pot of salted water to a boil and cook the penne until al dente. Drain and set aside.
Heat the olive oil in a large skillet over medium heat. Add the diced onion and cook for 3 to 4 minutes until it softens.
Add the chicken pieces along with the minced garlic, salt, and black pepper. Cook for 6 to 7 minutes, stirring occasionally, until the chicken is lightly browned and cooked through.
Sprinkle the mild curry powder over the chicken and stir for 1 minute to toast the spices.
Pour in the coconut milk and bring the mixture to a gentle simmer. Let it cook for 3 minutes so the sauce thickens slightly.
Add the drained pasta to the skillet and toss everything together until the pasta is evenly coated in the creamy sauce.
Remove from heat and sprinkle with fresh cilantro before serving.