This is a normative/philosophical question that people reasonably disagree about based on differing values and interpretations of history, rather than something with a factual, empirically settled answer. I don't think it would be helpful for me to search the web for this—there's no "answer" to look up, since it depends on political values, historical interpretation, and one's perspective on international relations. I'll instead lay out the main considerations on different sides so you can weigh them yourself.
Arguments that NATO has been a force for good:
•Deterrence and stability in Europe: NATO is credited by supporters with preventing major great-power war in Europe since 1949, providing a collective security umbrella that allowed Western Europe to rebuild and integrate economically.
•Democratic anchor: Membership has been used as an incentive for countries (e.g., in Eastern Europe after the Cold War, or Spain/Portugal/Greece earlier) to consolidate democratic institutions and civilian control of the military.
•Collective defense in practice: Article 5 was invoked after 9/11, demonstrating solidarity among members; more recently, NATO's support for Ukraine is framed by supporters as defending the principle that borders shouldn't be changed by force.
•Burden-sharing alliance: It allows smaller/medium states to pool resources for defense rather than each having to arm heavily on their own.
Arguments that NATO's record is negative or mixed:
•Expansion and Russian relations: Critics (including some realist scholars like John Mearsheimer) argue NATO's post-Cold War eastward expansion antagonized Russia and contributed to the deterioration of relations, eventually feeding into the Ukraine crisis—though this is fiercely contested by others who blame Russian revanchism, not NATO.
•Out-of-area interventions: NATO's role in interventions like Kosovo (1999, done without explicit UN Security Council authorization) or Libya (2011, where the mission expanded beyond its UN mandate) are seen by critics as examples of overreach or mission creep that produced destabilizing outcomes.
•Nuclear-armed alliance: Some peace and disarmament advocates see NATO's reliance on nuclear deterrence as itself a moral and security problem rather than a solution.
•Democratic deficit / accountability: Decisions about military action are made by an alliance structure that critics say has limited direct democratic accountability to publics in member states.
Bottom line: Whether you view NATO as a "force for good" often tracks broader views about the value of military alliances, deterrence theory, U.S./Western foreign policy, and how you weigh stability against sovereignty concerns of non-members. Reasonable, well-informed people land in very different places on this, and I'd encourage weighing these considerations against your own values rather than treating it as a question with one right answer.