If your talking about replacing the TIM with a coolant, then no...
I highly doubt any coolant has a higher coefficient of exchange then Gallium / Indium / Tin solder they use to solder the die directly to the IHS.
If were talking about older Intel CPU's that used paste under the IHS, well, we already delided a lot of those and replaced that junk tim with liquid metal.
Now if your talking about liquid coolants for liquid cooling systems:
We have had tons of those in the liquid cooling department for coolants.
And the concensus is they are not optimized or work really well to merit the cost increase in the thermal envelope our IC's run at.
Someone even thought the idea of using suspended graphine would be a good idea, but little to no research on his part to realize graphine is hydrophobic.
Ultimately it was determined that straight distilled with light additives to help against corrosion was the best recourse.
Typically we use proply glycol with dyes or suspended pearl effect dyes.
I do not run any additives in my coolant except copper 2 sulfate for anti microbe, and a silver kill coil.
But no... we gamers like bling and color, we really do not care about that extra .5C or less most of the occasion for the increase cost of 2x the price of distilled + antifreeze + dye. Even premix coolant are overpriced junk in my eyes, which one can easily mix at home, if they want it.
If you really want to go bells crazy on coolant, there is 3M Flourinert which is used also in military applications:
There are also liquid Gallium AIO's which again is mostly targeted at military:
But your nano coolant will lose by a VERY LARGE margin against a liquid metal coolant, so no.... it really has no market in the PC sector, when even a liquid metal AIO failed to take popularity due to its insane cost at the small performance boost because of a Big mean boss we call AMBIENT, that sits under the god almighty Thermodynamics.
Meaning thermodynamics makes things very difficult because ambient forces the wall which can not be passed without putting extra energy into the system. (compressed gasses / TEC / or using some form of endothermic reaction), but the last is typically only one way and cant be recycled like the first two.