Was NAM,NIEO a challenge to bipolarity …

Not at all because the reason was NAM nations were not strong as USA bloc and USSR bloc and these nations were known to THIRD WORLD NATIONS.

The term "Third World" arose during the Cold War to define countries that remained non-aligned with either NATO, or the Communist Bloc. The United States, Canada, Japan, South Korea, Western European nations and their allies represented the First World, while the Soviet Union,China,Cuba, and their allies represented the Second World. This terminology provided a way of broadly categorizing the nations of the Earth into three groups based on political and economic divisions.The Third World was normally seen to include many countries with colonial pasts in Africa, Latin America, Oceania and Asia. It was also sometimes taken as synonymous with countries in the Non-Aligned Movement. In the dependency theory of thinkers like Raúl Prebisch, Walter Rodney, Theotonio dos Santos, and Andre Gunder Frank, the Third World has also been connected to the world economic division as"periphery" countriesin the world system that is dominated by the "core" countries.