The pair both won automatic two-year cards to compete in all PDC ProTour events by winning outright spots on Sunday.
Former Players Championship Finals winner Nicholson had experienced Qualifying School for the first time this weekend after dropping out of the world’s top 64, but after reaching the last 16 on Friday and last eight on Saturday finally secured a top-four finish to retain his Tour Card without relying on ranking points.
He defeated Kevin Lane, Jordan Boyce, Mark Hylton, Richard Baillie, Gary Stone, Paul Cook and Bryan de Hoog on the day in Wigan, never losing more than three legs in a game and picking up two whitewashes along the way.
“I saw what John Part did on Saturday and I got a lot of motivation from that, and to win my Tour Card outright means a lot,” said Nicholson, who is the first player to be managed by ZWA and has been represented by the company since 2009.
“I felt like there was no pressure on me at all but I still want to be the kind of person who wants to win no matter what the prize is. It was a case of going to the end and being the last man standing.
“I wanted to keep on winning and get some confidence going into the UK Open Qualifiers, and that’s exactly what I’ve done.
“Last year I played some really good games which said to me that I can still live with the best standard, but the one thing that was missing was putting a run together of five, six, seven games in a row.
“If I’ve learned anything from Q School, that is it, to grind it out and get back to basics and do the right things at the right times. I did that today and I’m really proud of myself.”
Spanish star Alcinas also secured his return to the ProTour in style with whitewash victories in his final two games of the day, against Dean Forde and Jimmy Hendriks.
The six-time World Cup of Darts representative and two-time World Championship qualifier has missed out on winning back his Tour Card for the past two years, but also defeated Colin Osborne, Ron Seddon, Par Riihonen, Paul Phillips and Haruki Muramatsu on Sunday.