Bring a large pot of water to a boil, add salt to taste, and cook 1 lb fusili or rotini according to package directions until al dente. Drain and set pasta aside.
While the pasta cooks, heat a skillet over medium-high heat and add enough olive oil to coat the bottom. Add the 2–3 boneless, skinless chicken breasts cut into 1‑inch pieces. Sprinkle the chicken with 1 TB fresh thyme and salt and pepper to taste. Cook, stirring occasionally, until the chicken is cooked through and lightly browned (about 6–8 minutes). Transfer the cooked chicken to a plate and keep any pan juices in the skillet.
In a separate medium saucepan, melt 2 TB butter over medium heat. Add 2 TB all-purpose flour and whisk continuously until combined and slightly bubbly, about 1–2 minutes.
Add 2 tsp minced garlic to the roux and cook, whisking, for about 30 seconds to 1 minute until fragrant.
Gradually whisk in 2 c milk until smooth. Continue cooking over medium heat, whisking frequently, until the sauce thickens to a creamy consistency, about 3–5 minutes.
Remove the sauce from the heat and stir in 1 c shredded triple cheddar cheese until fully melted and smooth. Taste and adjust salt and pepper if needed.
Add the cooked chicken and the drained pasta to the cheese sauce. Return to low heat and stir gently until everything is evenly combined and heated through.
Sprinkle 2 TB fresh thyme and 1 TB oregano over the pasta, stir to distribute, then transfer to a serving dish.
Top with 1/4 c grated Parmesan cheese and serve warm.