The holding midfielder is continually being linked with a move to a bigger club, but the Nerazzurri have yet to make a formal offer
A number of recent reports suggested the Nerazzurri are keen to lure the Belgium international away from his current club this summer, but face stiff competition from Roma.
However, Moratti has downplayed his side's alleged interest in the 25-year-old.
"Nainggolan? I’m not sure if Inter are leading the chase for him. For now, we’re just looking," the Inter president told Sky Sport Italia.
"There’s no battle between us and Roma for his signature."
Nainggolan's contract with Cagliari runs out in June 2015, but Cagliari could opt to cash in on the midfielder this summer if a good offer comes in.