Season the chicken breast evenly with sea salt, black pepper, and dried oregano.
Heat the avocado oil in a medium skillet over medium-high heat.
Place the chicken in the skillet and sear for 5-7 minutes per side until the exterior is golden and crispy and the internal temperature reaches 165 degrees.
While the chicken cooks, mince the garlic clove finely.
In a small bowl, whisk together the Greek yogurt, lemon juice, Dijon mustard, and minced garlic until the dressing is smooth.
Roughly chop the romaine lettuce and place it into a large serving bowl.
Remove the chicken from the pan, let it rest for 3 minutes, then slice it into thin strips.
Arrange the sliced chicken over the bed of romaine lettuce.
Drizzle the prepared yogurt dressing over the salad and toss gently to coat.
Sprinkle with nutritional yeast and slivered almonds for a savory, crunchy finish.