Contestants included Kaitlin Cawley (10) from Sligo who wowed Nora with her specialist knowledge of American gangster Al Capone.
"She was very good at the general knowledge and knew things that I didn't know the answer to," said Nora, who described the 25 contestants as "a wonderful bunch of children".
And the children are taking to the hot seat better than the celebrities in the last series, Nora has revealed.
"They are absolutely amazing and it was also wonderful to see how relaxed they were. They seemed to be more relaxed than the celebrities."
Conor Nolan (10), from Carlow, also impressed Nora with his knowledge of inventor Thomas Edison.
She described how Conor told her that "he was going to invent a quiz machine that would get rid of me".
"He was a bit of an inventor himself and said he would invent a machine where they didn't need a quiz master," laughed the former Justice Minister and TV3 broadcaster.
Dubliner Callum Farrell (10) drew a laugh from the crowd and Nora herself while being quizzed on his chosen topic -- The Undersea World of SpongeBob SquarePants.
"I asked him the name of the ship that they used in the programme and the answer was SS Diarrhea," she told the Herald.
"The young fellow even smiled and I had to keep going with the questions and keep myself composed but all of the adults in the audience would have gotten a laugh out of that one."
The man behind the current series of Junior Mastermind -- Ben Frow -- is leaving TV3 at Christmas, which could spell the end of the show.
"They haven't got a lot of money. All the television channels are finding it hard to make ends meet," said Nora.
Some 25 children were handpicked from 100 applicants to take the hot seat for the quiz, which includes two rounds of questions each.
Just like the grown-up series, each contender has to answer questions about a specialist subject, followed by a general knowledge round.