Carefully remove bowl from pressure cooker and slide hard-boiled eggs onto cutting surface. Cut into pieces and transfer to a large bowl, along with diced celery, if using.
In a medium bowl, whisk together mayonnaise, mustard, lemon juice, salt, garlic powder and paprika, then season with fresh pepper.
Once combined, pour mixture over diced egg and toss together. Top with fresh chives or green onions.
