Which central panel is the last in chronological order (closest to the entrance)?

The last central panel in chronological viewing order, closest to the entrance, is The Drunkenness of Noah.

The nine central Genesis scenes are conventionally listed from the altar toward the chapel entrance. In that arrangement, the sequence ends with The Drunkenness of Noah, followed immediately before it by The Great Flood and The Sacrifice of Noah. The panel shows Noah after the Flood, when he plants a vineyard, becomes drunk, and is exposed by his son Ham while Shem and Japheth cover him.

This ordering can seem counterintuitive because the painted stories were executed from the entrance end toward the altar end. Michelangelo began with the Noah cycle near the entrance, so The Drunkenness of Noah was among the earliest central scenes painted even though it is the final panel in the narrative viewing sequence.

The nine panels are grouped thematically rather than presented as a strictly chronological reading of every event. The Creation scenes, Adam and Eve, and Noah’s family form three groups of three. The Great Flood is the central, large panel of the Noah group, while The Drunkenness of Noah closes the sequence at the entrance end.