In a pan over medium-high heat, melt butter, then add the chicken breast. Season with salt, pepper and oregano. Cook 8-10 minutes or until chicken is fully cooked. Remove from heat and set chicken aside.

In the same pan over medium heat, melt butter and add the garlic. Cook until the garlic begins to soften. Add half of the flour to the garlic and butter, stirring until incorporated. Then add the rest of the flour and stir.

Pour in the milk a little bit at a time, stirring well in between, until fully incorporated and sauce begins to thicken.

Season with salt, pepper, oregano and stir well to incorporate.
Add parmesan cheese and stir until melted.

Pour the sauce over cooked pasta, add the chicken and mix well.