Posters appeared in south Belfast last year making false claims about health workers.
This is the second time Mr Nicola has been questioned this year by police.
Mr Nicola, who is a prominent figure in the Roma charity RRCANI and was considered a face of the community in NI, has always denied involvement with the posters.
The posters, which appeared in the Holyland area of the city last year, falsely claimed that health workers working with the Roma community were paedophiles and involved in a child sex network.
Mr Nicola was arrested in February by officers investigating the content of posters and social media posts.
He was released on police bail, pending further enquiries. No charges were subsequently brought.
It is understood by The Nolan Show that Mr Nicola attended voluntarily, after new evidence emerged.
There have been a number of arrests as part of a wider PSNI investigation into alleged exploitation and criminality affecting the Roma community.
Earlier this month, Daniel Serban, 41, of Tildarg Street in Belfast, was convicted under the Communications Act of sending a message of a menacing character, which is understood to relate to sharing an image of the malicious posters online.
In a statement, the PSNI said: “A 30-year-old male was interviewed under caution last week and a file is currently being prepared for resubmission to the Public Prosecution Service”.
Det Insp Harvey thanked “individuals who have come forward so far” and appealed for anyone with concerns or information to contact the police.
Police added that a 32-year-old man is due to appear in court in relation to the offence of improper use of an electronic communications network.