Arno Nickel currently (2012) lives in Berlin and writes and publishes chess books through his well-known Edition Marco. Since 1983 he has been editing the German "Schach-Kalender", a pocket-calendar with about 1200 biographical player entries each year and a lot of information, stories, anecdotes, statistics, pictures and other things each year. From 1991 until 1994 he edited the "Schach-Journal" together with Alexander Koblencs, former trainer of Mikhail Tal. In 1996 he published Robert Hübner's famous book "Twenty-five Annotated Games". 2009 he published another book by Robert Hübner, this time in German language, with the title "Der Weltmeisterschaftskampf Lasker-Steinitz 1894 (UT:)und andere Zweikämpfe Laskers". Nickel is one of the world's leading correspondence chess players and freestyle chess experts.
In a correspondence match lasting many months, he won two games and drew a third against Hydra, the most powerful chess supercomputer in the world at that time (2005). Nickel, who achieved his grandmaster title in the era before GM-level chess computers, was allowed to use weaker personal computer chess engines to help him decide on his moves in this match. Hydra also received limited assistance from human chess experts and programmers, especially in choosing its opening book moves.
Since 2005 Nickel has been promoting Freestyle Chess, a new kind of online chess competition with computer-assisted play, where almost anything is allowed, also help from other players. He was a co-organizer of the series of PAL/CSS Freestyle Tournaments in 2006-2008, where teams of classic chess masters and grandmasters competed against correspondence chess and computer chess specialists as well as amateurs armed with computer chess engines. An unassisted human or unassisted computer playing alone has never won one of these events; the top prizes have always gone to human/computer teams (often with multiple humans and multiple computers on each team). In 2008 Nickel joined the InfinityChess project, which is a new chess server with its head office in Abu Dhabi. Amongst others InfinityChess has dedicated itself to Freestyle chess, while it basically supports four play modes: human, engine, centaur and correspondence chess. After early setbacks in 2009 the InfinityChess software has been developed completely new by a different development team, located in Karachi. The chess server announced his beta soft launch for January 15, 2012. 
In March 2007 Arno Nickel beat ICCF World Champion Joop van Oosterom in their correspondence game from 21st WC Final. Yet, van Oosterom won the Final and became a second time Correspondence Chess World Champion. Nickel finished fifth out of 15 finalists.
In 2006 Nickel started his first online correspondence chess game against the "World", i.e. the combined efforts of the users of ChessGames.com. Nickel resigned this game on January 11, 2007 after White's 41st move. A rematch started on August 25, 2008, which ended in a draw on February 25, 2009. About 1500 users participated in each of these exhibition matches. .
On February 16, 2009 Arno Nickel won the Simon Webb Memorial, a category 15 correspondence chess event with 13 grandmasters.
In the ICCF Champions League top group A, season 2007-2009, he achieved the best result on board 1.
In 2011 Nickel won the gold medal with the German olympic team in the Final of the 17th ICCF Correspondence Chess Olympiad. He achieved 8 out of 12 and the best result on board 3. 
With an Elo of 2648 his ranking in the ICCF rating list 2/2013 is No. 11 of the World.