Checking how much xp gives Nihl on basin wiki + info about xp penalty for level 98 + players 8 setting, to beat 2.5 million xp/hour you have to kill Nihl in less than 32 secs to be more efficient leveling target. From what I see, Nihl has 0 physical resistance and ~120100 HP on p8 with 50% block... I believe well built smiter can kill him in 3 secs of smiting, even faster if we include Reaper's Tool on merc, but I didn't look into it in depth... I don't see a reason why pala shouldn't be able to deal with Nihl faster than 25 secs at average if barb can do it in 21.5 secs. Grief (1.07 eth atma bugged BA best) + spirit shield + all in to have maximum smite damage + maxed fanaticism + 8 skillers + etc etc. Don't know what kind of dangers are at Nihl area, but if you kill him in few secs, I guess you won't stay there for too long to find out.