To Hard-boil the eggs---In a 4 quart saucepan or Dutch oven, place eggs in a single layer. Heat to boiling, Immediately remove from heat and cover and let stand for 15 minutes. Drain and then rinse with cold water. Place eggs in a bowl of ice water and let stand for 10 minutes.
To remove the shell, crack it by tapping egg gently all over; roll egg between hands to loosen the shell. Start peeling at the large end.
Cut eggs in half lengthwise. Into a medium bowl, slip out the yolks and mash with a fork. Stir dressing mix, mayonnaise and mustard into the yolks.
Spoon or pipe the yolk mixture into the egg white halves. Sprinkle with chives. Refrigerate at least 30 minutes prior to serving.