Nicholson says front rowers Taite Smith and Tama Renton were standout players, while hooker Sam Johnstone earned his third-consecutive player of the day award.
The Mariners have more travel ahead as they take on the Wellington Orcas in Wellington this weekend.
"We are under no illusions we are the newbies in the competition. Wellington are the heavyweights and they will be tough and well structured. It will be a big ask, but like any David and Goliath situation, we are not going down to lose and we will give it everything we have got.
"The trip away was really good. The team bonding the night before, a good breakfast and a team walk – all that sort of thing is getting to know each other and, as well as playing more games together, it is coming together well.
"We need to keep improving. As each game goes the combinations are getting better. We are still missing tackles, that is a work on and we need to make ourselves accountable for those kind of things."
North Island Championship results:
Taranaki Sharks 28, Wellington Orcas 42.
Northern Swords 36, Coastline Mariners 24.
Draw for Saturday, September 14:
Wellington Orcas v Coastline Mariners, Porirua.
Taranaki Sharks v Manawatu Mustangs, Waitara.
Northern Swords, bye.