Since suffering a first loss to Dmitry Chudinov in June last year and moving up to 168lbs, Nielsen has dominated his opponents and Saturday was no different.
All three judges could only give Acosta a solitary round as Nielsen moved on to 25-1 and potentially towards some sort of title shot in the late summer.
In the co-feature bout, Klara Svensson missed the chance to win the coveted WBC super lightweight title as Erica Faria kept a firm grip on her green belt.
Svensson was favoured by many to overthrow the Argentinian world champion, although came up short after a ten-round battle.
Farias, 30, took the decision with all three of the judges 98-92, 96-93 and 96-94 to move to 22-1 as Svensson drops to 15-1 with a maiden defeat.
Also on the bill, Oscar Ahlin and Abdul Khattab both suffered first career defeats after losing out to eleven and four-loss Ben Donfack and Howard Cospolite respectively.
‘Golden Boy’ Ahlin found Donfack a tough customer from the word go and couldn’t get out of second gear to take control of the fight.
In the end, judges awarded 34 year-old Donfack a deserved triumph 77-74 (twice) and 76-74 on the cards to improve him to 22-11-3. Ahlin, 25, now has a record reading 12-1.
Khattab, 22, also dented his 11-0 record as Cospolite halted him in the fifth whilst ahead on two of the three judges scoresheets.
Swedish heavyweight Otto Wallin made it eleven wins from eleven with a fourth round knockout victory over Georgian Beka Lobjanidze.
The hard-hitting southpaw emulated Dillian Whyte’s efforts when the Briton inflicted a first defeat on Lobjanidze in February and Wallin, 24, remains unblemished as a professional.
Young super middleweight Tim-Robin Lihaug made easy work of Istvan Zeller as the Norweigan moved to 12-1 with a seventh stoppage win.
The 22 year-old was on top for as long as the contest latest until getting the Hungarian out of there midway through the third round.
Earlier, Rashid Kassem knocked Anto Nakic out to remain undefeated, whilst light heavyweight Alexander Hagen and super middleweight Simen Smaadal both carded unanimous decisions.