Why is Poland worried about invasion? Isn't it a NATO-member country?

ANSWER: Yes, Poland is a NATO-member country, but many in Poland do not seem to trust their NATO membership to protect them, especially after seeing how spinelessly NATO has responded to the invasion of Ukraine. 

NATO seems willing to give Ukraine to Putin in exchange for Putin's promise not to attack NATO-member countries and not to aggravate "climate change" by using nuclear weapons. But what if Putin wants another country after Ukraine, even if it is a NATO-member country? Will the remaining NATO-member countries try to negotiate with Putin again by saying, "Okay, you can have one more country, but you have to promise not to nuke the rest of us."