There's a couple counters for it like Lulu, Lux, Tahm, and Braum. But these counters aren't really great against it. The real counter against Nunu support is Alistar. But you can just ban that piece of cowsh!t, so that's no problemo.
But other than that, you really have free knock up and poke and trades with just snowball down the lane. It'll shove the lane, force enemy off the waves to run away from snow ball, and if they get caught, your ADC can just free trade it and walk away.
Been playing it and it's really easy to start winning lane and start roaming consistently. You can thank me later.