Nainggolan is on-loan at Cagliari from the Nerazzurri.
And he said: "(Marcelo) Brozovic, who always does his best at Inter, always plays well and is doing a lot.
"(Nicolo) Barella is showing he's a great team player, at his age he's showing a lot."
Nainggolan added: “I always feel a bit Sardinian, which is why I came back, the year of the centenary and they made important investments even if it hasn't gone very well lately. We've taken a bit of satisfaction out of it though and I think we're thirteen games away, we're always there, football has to be played and we'll see."