The decisive moment arrived in the 88th minute at the King Baudouin Stadium. Olise collected a pass from Rayan Cherki on a quick break, drove forward and finished low into the bottom corner to secure the three points for Les Bleus.
The match had remained goalless until the closing stages despite France enjoying the majority of possession and creating the clearer chances. Goalkeeper Mike Maignan produced an important save earlier in the second half to keep the score level.
The result marks a second successive win for France under new head coach Zinedine Zidane, following their opening victory over Türkiye. France now sit top of Group A1. Belgium, who had beaten Italy in their first match, suffered their first defeat of the campaign under Mark van Bommel.
Kylian Mbappé was absent through injury after picking up a problem while scoring in the previous fixture. Zidane introduced several attacking substitutes, including Olise, Cherki and Ousmane Dembélé, as France pushed for a breakthrough.
The late winner provided a significant boost for the French side as they continue their Nations League campaign. Both teams will meet again later in the group stage.