While the result has little bearing on either country's finishing position, Roberto Martinez will be relieved to have avoided a second successive draw heading into the crunch clash with Switzerland, that will determine which team advances from Group 2 in League A.
Belgium already needed only a draw from that match but will still boast the mental edge of being three points clear courtesy of Batshuayi's brace.
The 25-year-old had to wait until after the hour for Eden Hazard's genius pass to help him break the deadlock before he feasted on a kind rebound to put the match to bed in Axel Witsel's 100th international appearance.
UEFA Nations League (@UEFAEURO) November 15, 2018
Romelu Lukaku's hamstring injury created a starting opportunity for Batshuayi, who struggled to find his range in the opening 20 minutes.
The Valencia striker, out of form at club level, first skied an intelligent low cross from Dries Mertens and guided his next chance against the outside of the near post after turning Kari Arnason.
Mertens brought an initially uneventful second half to life by testing the upright with a clever free-kick, but it Hazard always appeared most likely to make the difference.
The star playmaker conjured the killer pass to prise open Iceland in the 65th minute, bisecting the back five with a superb ball that Thomas Meunier squared for Batshuayi to tap home.
Thibaut Courtois was finally worked with 15 minutes remaining and passed the test, keeping out Albert Gudmundsson's meek finish.
That allowed Batshuayi to add the icing in the 81st minute, his second a simple follow-up following Hannes Halldorsson's fumble of substitute Hans Vanaken's shot.
What does it mean? Swiss can still get the chocolates
That an Iceland side enduring a miserable winless run managed to keep their more fancied opponents scoreless for over an hour should provide hope to Switzerland of doing likewise, even accounting for their troubling recent loss to Qatar.
The challenge for Vladimir Petkovic's team will be to ally attacking incisiveness to defensive discipline given they must score at least twice.
Hazard the headline act
Given freedom to roam, Hazard picked up the slack in Kevin De Bruyne's absence as he did almost all of Belgium's probing in the compact space between Iceland's defence and midfield, eventually delivering the splendid pass that broke the game open.
Arnason at sea
He was at times tasked with too much considering there were two central defenders either side, but Genclerbirligi man Arnason had a tough time coming to grips with Batshuayi, often engaging when he could have dropped off.
The Red Devils round out the group stage away to Switzerland on Sunday, while Iceland remain in Belgium for a friendly meeting with Qatar on Monday.