If you are set on NB I'd suggest Restoration staff as a complete heavy attack return magicka and combine it with mostly Siphoning and a few Shadow abilites.

If you want to heal in groups I strongly suggest you morph Strife into Funnel Health. Even if you don't play as a healer it helps the group.

Agony can be useful at times, it's a mez with a DoT attached when in breaks early or timer runs out. Malefic Wreath is the morph I'd suggest and the reason is that it delivers all damage once it breaks instead of a DoT. You can't reapply Agony and the Prolonged Suffering morph until the DoT has run it's course, something to consider.

Cripple morphed into Crippling Grasp, more damage on hit and immobilize.

Siphoning Strikes morphed into Siphoning Attacks for a caster as this morph can trigger on offensive spells, it works very well with Force Shock from the Destruction staff as it seems to proc alot more, probably due to the Force Shock delivering 3 different types of damage on hit.

Power Drain is personal preference, if you feel the need for more survivability against large groups of mobs you'd do well with the Sap Essence morph, and it heals the group as well, Power Extraction if more powerful but doesn't heal, it's really up to you but by the time you unlock this you should probably know.

Soul Shred I'd go for Soul Siphon if you are really dedicated to healing, otherwise Soul Tether.

In Shadow you'll find Path of Darkness, it's similar to the Destruction staff Wall of Elements but with a longer duration, it can be morphed into a version that heals you or friendlies as well as damage them or one that does more damage and a much larger area.

Aspect of Terror is a fear that can be morphed into a stronger version that debuff, but it can be risky waiting for the big bad monster to get in your face before you cast it, the other morph Manifestation of Terror changes it to become a trap cast at your feet and affects more targets, it takes a couple of seconds to arm, and it's safer as you can place it between you and the mob giving you the option to keep out of harms way.

Summon shade is just a debuff that is rooted to the ground, morphed to Shadow Image you can teleport to it once or if you pick the other morph Dark Shades it summons 2 melee shadows that move to the target.

And finally, one of the best ultimates in the game Consuming Darkness morphed into Veil of Blades, huge mitigation for yourself and friendlies while standing in it and does damage as well, this will probably be your goto ability when facing difficult encounters.

In Assassination you can pick up Assassin's Blade and morph it into Impale for a ranged execute.

Should give you an idea of what to look forward to and get started.

Thank you Armann, this was very much helpfull

I read many places that it is recommended to put all points in Health, but I find it realy strange to be honest should I rely only on enchanting to boost my Magicka pool and regeneration?