Never Stop Running makes a lot of sense for this concept. Good catch!
And, this build is actually very similar to one I beat Nightmare with recently (and quite easily, I must say.) Except mine was based on the Adventurer class. Off the top of my head, it was something like -
Talents:
Cunning/Stealth 5/5/1*/5 (about the same as yours - * = see below)
Spell/Temporal 1/5/1/5 (same)
Spell/Admixtures 5/5/5/0 (great physical AoE damage - yum)
Spell/Stone 5/1*/1*/5 (Crystalline Focus!)
Spell/Phantasm 5/5/0/0 (same - probably overkill with Admixtures running, but it's useful early, and I like the status)
Psionic/Absorption 1/0/0/0 (free staff slot!)
* = plus 4 extra points I moved between Body of Stone and HiPS (or Earthquake, at one point) as I saw fit. Throughout High Peak, I used them to max Body of Stone (which I almost never used, HiPS would probably have been better.)
Generics:
Combat Training 5/1/5/0/0 (yes, 5 Accuracy! Seems overkill, but I really liked it when silenced with my wilds on cooldown)
Spell/Conveyance 5/1/0/0 (same)
Celestial/Light 3/5/5/? (about the same, can't remember exactly how much I spent on Providence except I didn't max it)
Spell/Staff Combat 5/5/?/0 (about the same, I wanted to max Defensive Posture but couldn't)
Spell/Alchemy 5/5/1/0
Race was Cornac, maxed stats were MAG, CUN, DEX, with leftover points to CON (I didn't max Thick Skin until very late), with 5 inscriptions: phys/mental wild x 2, movement, heroism, shield. (No manasurge rune, I got rid of mine after I found Tarelion's staff (gives lots of mana on crits) but even without it, as long as you have ~200 free mana and some mana regeneration from items, you should be fine. Channel Staff, Illuminate and bombs only cost 5 mana/use. ) Prodigies were Arcane Might and Crafty Hands. Also, I catpointed Staff Combat.
So, on top of Channel Staff and Illuminate, this one adds bombs (for better AoE damage) and Earthen Missiles (for an extra bit of punch and range, but mainly for quick bone shield removal.) Also, decent at hand-to-hand combat (not that you should try that if you can avoid it, of course!)
From escorts (CPD, Time Prison, and Healing Light all came in handy here) I got 1 each of Heightened Senses, Piercing Sight, and Arcane Eye, and increases in Celestial/Light and Staff Combat. No Premonition, sadly, but I didn't build any WIL to sustain it anyway. No Chant of Fortress either, but I did fine without it.
I was tempted to side with the Assassin Lord and catpoint both Stealth (to 1.4) and maybe Cunning/Scoundrel (to 1.1), because of the heavy investment on Earthen Missiles (which causes bleeding and thus works well with the Scoundrel talents), paying for that with Crafty Hands, Stone Alchemy 5/0/0/0 and an inscription slot (you still get Nimble Movements to compensate.) This would be an interesting build, but being able to alchemize and not saving the merchant seemed both unproductive and unappealing

, and throughout the run I found out that Stealth with just 1.00 mastery was about enough with 8+ range spells anyway.
Another interesting option would be to get Chronomancy/Gravity in lieu of Spell/Phantasm, and maybe use the Rune of the Rift to manage Paradox. Healing Light, especially, works much better when you can pin mobs or move them away so they don't benefit from it
Yet another option: Psionic/Mentalism at 1/x/0/0. Mental saves were my worst problem by far.
Note that this build can't really work with Yeeks, Dwarves and the undead races, as ideally you want to get Staff Mastery from Angolwen (paying for it with alchemy and transmo'ed gems), and you have zero offensive capability early. To make it work, you have to skip the character creation screen (at least don't invest in magical talents), go to Zigur and buy a (good) torque of mindblast here. If there isn't any for sale, start a new character.
As I said, my run was quite easy (for a Nightmare run, at least.) I farportaled a lot more than I use to at this level, found a lot of cool items (notably "dual-wielding" Bolbum and Tarelion's staves - ouch!), and hit level 50 way before High Peak. (Oddly enough, it was only then - playing a level 50 character with great equipment in every slot, imbued with unique gems - that I started dying.)
Final notes:
- on TK Grasp: you'll want a good staff in the extra slot, but since you're not building any WIL it's better to keep Beyond the Flesh OFF most of the time. Turn it on only when in hand to hand combat, especially if it's a high-damage staff like Bolbum's.
- on equipment: besied the obvious things to look for (+spellpower, crit multiplier, etc.), because of the high DEX and defensive sustains (Blur Sight and Defensive Posture), this build benefits a lot from equipment that increases defense. Also, because of the Shadowstrike (autocrits) + Channel Staff (to prime the pump) combo, items that stack spellpower on crits (e.g., Spellblaze Echoes) are more useful to you (or at least, much easier to take advantage of) than to any other build. In other words, be polite, be civilized, and remember to knock 3 times on each door before entering
