Question: I suspect being economically strong and independent aren't enough to become a super power in today world, I realised that US is slowly losing it's grip as a super power after it starts shifting focus on other research areas and staying away from making nukes. Given today technology, can a nation become a super power without having any nuclear programme? Sorry for my childish thinking but I think people would definitely listen when you can talk at over 250dB.

Answer: 
That is unknown ...
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Nuclear weapons have not been used in combat for almost 75 years. Their existence has loomed over geostrategic thinking, but nuclear strategy are all **untested assumptions.**

Once upon a time, [theorists](https://en.wikipedia.org/wiki/Herman_Kahn) wrote papers where widespread *evacuation* programs were seen as more significant than localized nuclear use. Others [seem](https://en.wikipedia.org/wiki/Force_de_dissuasion) to have thought roughly "any nuke is a nuke" and their very first strike would be a massive [countervalue](https://en.wikipedia.org/wiki/Countervalue) attack.

I consider it *quite* feasible that a major non-nuclear power could come close to superpower status using trade, cultural influence, and cyber power. Would they actually be a superpower? People would argue endlessly.

Consider virtual arsenals.
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Remember how upset the US are/were about Iraqi, Iranian or North Korean nuclear weapon programs? Well, South Korea, Japan and Germany presumably have no nuclear weapon programs, but their non-existing programs are much closer to the bomb than, say, Iran. And Japan probably could overtake North Korea in a few months, if they wanted to. They are *trusted* not to take that step.

* They have scientists who understand nuclear weapons engineering, if only so that their national security agencies can *evaluate reports* of other countries' programs. They would never rely on intelligence from the P5 alone.
* They have a civilian nuclear industry with plutonium stockpiles.
* They have at least tactical delivery systems.
China does have nuclear weapons, but I have never heard people citing it when arguing that China is now superpower.

They usually cite their GDP (PPP) or exports in $bn.

If that is not sufficient, consider an non-nuclear but economically powerful country with a close ally (maybe a client state of sorts) in the same military block which has some nuclear capacity but does not qualify as superpower otherwise.