Yes, you can create one nudge of each type. So if you really want a date nudge, a tax reserve nudge and an excess balance nudge, then that is just fine. Set them all up.
If you decide to make allocations into different money pools for one or more nudges, and two (or more) of you nudges 'clash' on any given day (i.e. multiple nudges are trying to send you a notification on the same day), you will receive a single notification that simply adds up the contributions of what the individual nudge notifications would have shown.
This is a very easy way to make sure you are saving exactly what you want, when you want with the minimum of effort and maximum control.