There’s a new plug-in available for Audacity 1.3 called Beat Per Minute labels. (available here: https://forum.audacityteam.org/t/beat-per-minute-labels/20785/1 )
It creates a label track with bars and beats marked at the tempo specified. When dragging an audio clip to a label position, labels are slightly “magnetic” so the audio clip will tend to snap to the label position.