The alpha dog does not squeal when nipped. You should be the alpha dog, not a litter mate. Making a noise like that shows excitement, which to an already unstable minded dog, only compounds the problem.
Being the alpha is a mindset. If you watch an alpha dog, they get what they want by intimidation 99% of the time. There is very little aggression but a lot of persuasion. This is why you don’t take things off a dog, you persuade them to drop whatever it is, then remove it.
Being the alpha is very much about mindset, posture, willpower, stubbornness, eye contact and voice tone.
When the dog nips, straighten up and assume a commanding posture / mindset. I usually say calmly but firmly “hey” in a particular tone. They know immediately that what they just did is not acceptable and that I am serious. I also hold my hand out (not closely too them) with the palm towards them. Also, never underestimate eye contact, the alpha uses it’s eyes a lot. Notice most dogs when you stare at them will stare back and then look away.
Always stay calm, never angry and always be fair.