In a small bowl, whisk together sour cream, buttermilk, herbs, vinegar, pepper, and salt. Set aside.
In a medium saucepan over medium heat, stir together cream cheese and hot sauce until smooth.
Add chicken, 1 cup smoked cheddar, 1 cup sharp cheddar, and ½ cup green onion. Stir until cheeses melt.
Stir in sour cream mixture until combined.
Spoon mixture into a 1-quart baking dish. Sprinkle with remaining cheeses.
Preheat broiler to high. Broil, watching carefully, until cheese is golden brown and bubbly, about 4 minutes.
Remove from oven; garnish with remaining ¼ cup green onion and almonds.
Serve with tortilla chips, celery sticks, and/or crostini.