Nielsen reckons Helenius is more than a goal-getter and the 51-year-old coach reckons his fellow countryman can also play an important part creating chances.
The forward is 6ft 5ins tall, but his former mentor claims he is more dangerous with his boots than he is with his head.
"Nicklas has very good vision," said Nielsen to the Birmingham Mail. "Last season he was not only our highest scorer, he also made the most assists. He is always aware of his team-mates and he has a very good pass.
"He's also very lively during matches and will always cause problems for the opposition.
"He scored a lot of goals at under-17 and under-19 level, and he has continued scoring for the two-and-a-half years I have been at the club. He scored a few goals with headers last season but his main strength is his shooting.
"He hits the ball so hard it's unbelievable. He is very strong from distance and is very precise. A lot of his goals have been scored from the edge of the penalty area, but he can also score what you would call easy goals."