You can nudge by tick, but not in ms unfortunately...
However, it's possible to delay a region by ms. Here's how :
1-In the Inspector, control-click (or right-click) the delay parameter.
2-Check "delay in ms".
3-Click-Drag up or down on the value to change it.
Please note that if you double-click and enter a value, you'll need to enter it in ticks (not in ms) and Logic will do the conversion.
Hope it helps!