Place the chicken breast in a pot, cover with water, bring to a boil, then reduce heat and simmer for 18 to 20 minutes until cooked to 165°F / 74°C.
Remove the chicken, let it cool for 5 minutes, then shred it into bite-size pieces using two forks.
In a large bowl, whisk together mayonnaise, sour cream, lemon juice, garlic powder, onion powder, black pepper, and salt until smooth.
Add the shredded chicken to the bowl and toss until every piece is evenly coated with the creamy dressing.
Serve immediately on bread, crackers, or lettuce, or refrigerate for up to 3 days in an airtight container.