Not expert on .io domains but I can see tons of similar sales from park.io, usually in XXX range.
According to google results many businesses have NUNU name in it so it may be a promising one.
its nice cvcv .. might be some new startup would pick it up in range of 500-1000 usd but u need patience and second disadvantage is renewal.. i would hold on this for 2 years with price tag of 995 USD