For an effect that includes Nucleus objects, a Nucleus node is published to the asset. To make the effects asset collide with an object, you can select Effects Assets > Collide with Effect. This converts the selected object to a passive collision object and assigns it to the asset's Nucleus solver. If the object is already associated with another Nucleus solver, selecting Collide with Effect re-assigns the object to the asset's Nucleus solver. See nSolver > Assign Solver.

To make objects collide with a fluid that is in the effect, you can select the fluid object, which is an internal node in the asset, in the Outliner. You can then make the fluid collide with objects as with normal fluids. See Make fluids collide with geometry.