Season the chicken breast evenly on both sides with sea salt, black pepper, and dried oregano.
Heat the olive oil in a medium non-stick skillet over medium-high heat.
Add the chicken to the skillet and sear for 5-6 minutes per side until golden brown and cooked through, then remove from the pan and set aside to rest.
In the same skillet, add the minced garlic and sauté for about 30 seconds until fragrant, being careful not to burn it.
Add the dry orzo to the skillet and stir for 1 minute to lightly toast the grains.
Pour in the chicken broth and lemon juice, scraping the bottom of the pan to release any browned bits.
Bring the liquid to a boil, then reduce heat to low, cover, and simmer for 8-10 minutes or until the orzo is tender and most liquid is absorbed.
Slice the rested chicken into strips and return it to the skillet along with the fresh spinach, tossing gently until the spinach is wilted and everything is well combined.