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: 
**First to achieve Lunar/Space Colony.**

Say a multibillionaire sets his sights on space exploration. Before the slow engines of states achieve similar success, his country could be lauded SuperPower if they get first De FACTO ownership of celestial bodies.

The logistical capabilities that accomplishment grants, the information available to them. 

*And the sheer Bragging Rights.*

That makes you the sole state who controls a rare commodity, akin to China holding the Lion's share of rare earths.

Remember that Politics is the Art of looking the part.
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.