Season the chicken breast evenly with sea salt, black pepper, and dried oregano on both sides.
Heat the olive oil in a large skillet over medium-high heat until shimmering.
Add the chicken to the skillet and sear for 5-7 minutes per side, or until golden brown and cooked through to an internal temperature of 165°F.
Remove the chicken from the skillet and set aside on a plate to rest.
Lower the heat to medium and add the minced garlic and chopped sun-dried tomatoes to the same skillet, sautéing for 1 minute until fragrant.
Pour in the chicken broth, coconut milk, and nutritional yeast, using a wooden spoon to scrape up any browned bits from the bottom of the pan.
Add the fresh baby spinach to the liquid and stir constantly until the leaves are wilted and the sauce has slightly thickened.
Place the chicken back into the skillet, spooning the creamy sauce over the top, and simmer for 1-2 minutes before serving.