Combine kosher salt, black pepper, garlic powder, onion powder, smoked paprika, dried thyme, dried oregano, and cayenne pepper (if using) in a small bowl or jar.
Whisk well until evenly blended, or secure lid and shake until no clumps remain.
Store the seasoning in an airtight container in a cool, dark place for up to 6 months.
When ready to use, rub 1–2 tablespoons over a whole chicken or sprinkle about 1 teaspoon per pound of chicken pieces.
Let seasoned chicken rest at room temperature for 15 minutes or refrigerate for up to 2 hours before cooking.