CADIZ, April 5, 2014 (AFP) - Nixon, who before this tournament had made just one European Tour cut this year in finishing joint 27th at February's Africa Open, carded a seven under score of 65.
His only black marks were dropped shots at the par four second and the par five 11th.
"I played really nicely. I don't remember much about it apart from the fact that I kept knocking them close and knocking the putts in," he said. "If I could do that again tomorrow it would come in handy."
Nixon, still without a European Tour win after four seasons, leads by one shot from Italy's Marco Crespi, who went round in six under.
Crespi is one stroke clear of Chile's Felipe Aguilar, who led midway through a round delayed to allow much of the field to complete their second round in the morning.
Portugal's Ricardo Santos was one behind Aguilar, in turn one ahead of a quartet on four under.
Leading third round scores in the Cadiz Open on Saturday (GBR/IRL unless stated, par 72):
208 - Matthew Nixon 72 71 65
209 - Marco Crespi (ITA) 70 73 66
210 - Felipe Aguilar (CHI) 71 69 70
211 - Ricardo Santos (POR) 74 70 67
212 - Tjaart Van Der Walt (RSA) 70 73 69, Richie Ramsay 71 72 69, David Horsey 71 68 73, Adrian Otaegui (ESP) 71 69 72
213 - Damien McGrane 74 69 70, Kristoffer Broberg (SWE) 76 70 67, Scott Jamieson 71 72 70
214 - Marc Warren 72 67 75, Jordi garcia Pinto (ESP) 73 70 71, Matteo Delpodio
(ITA) 71 73 70, Oliver Fisher 71 72 71
215 - Andrew Johnston 73 72 70, Lucas Bjerregaard (DEN) 72 73 70, Daniel Im (USA) 72 72 71, Rhys Davies 72 71 72
216 - Sihwan Kim (NOR 70 76 70, David Howell 71 75 70
217 - Lasse Jensen (DEN) 73 70 74, Estanislao Goya (ARG) 73 75 69, John Hahn
(USA) 74 68 75, Jens Dantorp (SWE) 71 73 73, Mikko Korhonen (FIN) 71 75 71, Johan Edfors (SWE) 76 72 69, Jamie McLeary 73 70 74, Connor Arendell (USA) 72 75 70, Phillip Archer 74 70 73, Carlos del Moral (ESP) 73 72 72, Lorenzo Gagli (ITA) 71 74 72, Bradley Dredge 70 69 78