I feel like when effective stacks are down to 10 bbs i'm probably calling all ins to tight.

I looked at the nash calling chart for this stack size and i don't understand how it works. Is it literally only worth playing if opponent is playing push/fold at this stack depth? If this is the case and as pretty much every opponent i play is an unknown i can never know if this is what they're doing at this stack depth.

Also if i somehow know they're playing push/fold i still don't see how the chart is helpful. What if for example when they're on 6 bbs they're only shoving Ax, Kx, broadways and pps. It says on the chart i should be calling with hands like J,6o but this would be a mistake against that shoving range.