As of Thursday morning, around $230,000 (£173,000) had been raised, with another $70,000 needed for the campaign to be able to buy up all of the 10,000 seats which the organisers of the Rio 2016 Paralympics have agreed to allocate to it.
However, the idea of sending 10,000 children to the Paralympics - the opening ceremony for which was on Wednesday night - was not even a consideration a few weeks ago, when Nugent simply wanted to raise enough money for a small number of Brazilian schoolchildren to go.
At that stage, just $1,000 was sought. But he was able to get the money so quickly by phoning around friends, that a more ambitious target of $15,000 was set – to enable 500 children to get tickets - he told PRWeek UK.
That was on 23 August. The next day the campaign received an unexpected boost when Coldplay, who had played at the closing ceremony for the 2012 Paralympics, came out in support of the campaign.
Nugent, the former director of brand, marketing and culture at London 2012 and now a non-executive director of the British Paralympic Association, told PRWeek:" The thing that changed everything was Coldplay really if I’m honest - it went stratospheric."
He added: "Nearly every day something has been happening that was never planned and I think this is a really important part of this. It is not pre-planned, it wasn’t destined to succeed."
Another key boost came when the International Paralympic Committee and Rio 2016 gave their formal backing to the initiative and said it could buy up to 10,000 tickets at $30 (£22.50) each, a few days after Coldplay's endorsement. The profile of the #filltheseats campaign rose even further this week, when Prince Harry made a personal donation.
Prince Harry has made a personal donation to #filltheseats so Rio kids can see Invictus & Paralympic competitors in action. Enjoy the games!— Kensington Palace (@KensingtonRoyal) September 6, 2016
Companies such as Allianz, Mars UK, and Sainsburys have also made donations.
In Nugent’s view, the simplicity of the idea has been the key to its success. "The absolute truth is that I don’t think you could orchestrate something like this because it has just taken on its own momentum and it’s a really positive one."
He commented: "This literally has just been me taking about a week and a half off work. This is something that just caught people's attention and that people have liked, so there's no team, no nothing, it's just happening."
Any money raised over and above the $300,000 target will go to charities in Brazil connected with disability sports, if they are unable to buy more than the 10,000 tickets already reserved by the organisers of the Paralympics.
He remains optimistic that the scenes seen at the Rio Olympics of empty seats at venues will not be repeated. "They’ve actually now sold over 1.6m tickets for the Paralympics and that is significant. No one wants to see the venues looking like they did with the Olympics."
Reflecting on the unexpected success of #filltheseats, Nugent said: "This is seriously just something that is so unplanned it’s untrue, and the momentum behind it is all natural, which I think is the powerful thing." He added: "The only thing which has worked, which I've spent a lot of time thinking about, is how simple this idea is. The feedback I'm being given is 'you just made it really simple for me to help'."