Pandiani was born in Montevideo, Uruguay, the eldest of three sons of Uruguay internationalstriker Walter Pandiani. The family moved to Spain after Walter established his career there. Nico played in the youth system of CE Premià, and had linked up with the junior teams of Espanyol in 2012–13 pre-season as part of a trial, but then followed his father to Villarreal in August 2012, where he was to play for the club's C team. In January 2013, the pair moved on to Segunda División B club Atlético Baleares, where son as well as father signed a first-team contract. Pandiani made his league debut on 14 April, as a second-half substitute in a 2–0 win away to Levante B, and played once more, starting the penultimate game of the season, a 2–1 defeat away at Sant Andreu, in which his father scored the opening goal. In late October 2013, Pandiani and Walter returned to Uruguay to joinPrimera División strugglers Miramar Misiones, where Walter hoped to fulfil his dream of playing professionally in the same team as his son. Pandiani was ineligible to play in the Apertura, and he finally made his professional debut – under his father's captaincy – on the third matchday of the Clausura, on 16 February 2014 away to El Tanque Sisley. Miramar lost 1–0, and Pandiani failed to clear the ball that set up the goal for the hosts. He played once more before relegation was confirmed with five games still to play, and then started the remaining matches to bring his total appearances to seven. For the 2014–15 season, Pandiani returned to Spain and signed for Segunda B club Marino de Luanco. He made his debut on 20 September as a very late substitute in a 2–2 draw at Atlético Astorga, and made 13 league appearances over the season. His team struggled throughout the campaign, and finished 15 points adrift at the bottom of the division. Pandiani left Luanco at the end of the season and returned to Uruguay, where he trained with and was reported to have signed for Canadian of the Segunda División. Although expected to start the opening match of the season at the end of October, administrative issues related to international clearance prevented his appearance. A few days later, Spanish Tercera División club Masnou announced his arrival on a contract to the end of the 2015–16 season.