For one thing, you're over by 50 points (2050).
My first suggestion would be to that you need more heroes. Nighthaunt rely on their heroes for buffs and support, and you don't have enough.
Secondly, try to take full units if you can to benefit from the max-unit discount. For example, 2 units of 15 Bladegheists costs 540, but a unit of 20 and a unit of 10 would cost 500. 2 units of 20 Chainrasps cost 320, but a unit of 40 costs 280. Those points add up when you start reshuffling your units.
2x Chainguard is a real waste, considering you can only cast a spell once per turn (regardless of if it succeeds or is unbound), so only one unit of Chainrasp will benefit from Spectral Lure and Temporal Relocation. The other 3 get left in the wind. Additionally, you're better off having one unit that gets all the buffs, rather than try to spread them out between two.
You can start with the 2x battalions, but honestly, none of the Nighthaunt battalions are particularly good, and it's a balancing act of taking battalions to reduce drops and give artefacts/command points, vs spending too many points on them that could have been used for more stuff.
For example, in this army you've spent 350 points on battalions. You know what else is 350 points? 30 Grimghast Reapers (360, but close enough). I would rather have the Reapers over the battalions.
On that note, I know it's not in your collection, but I would highly recommend getting a max unit of Grimghast Reapers. They're a phenomenal battleline unit and because of their built-in rerolls to hit vs targets of 5+ models, they don't need too many buffs to do work.
I would rejig the list as follows:
Knight of Shrouds
- Artefact: Midnight Tome (Lore Spell: Shademist)
Spirit Torment
- General (Ruler of the Spirit Hosts)
- Artefact (Pendant of the Fell Wind)
Guardian of Souls with Nightmare Lantern
- Artefact (Wychlight Lantern)
- Lore Spell (Soul Cage)
Guardian of Souls with Mortality Glass
- Lore Spell: Spectral Tether
40 Chainrasp Horde
10 Chainrasp Horde
20 Bladegheist Revenants
10 Bladegheist Revenants
30 Grimghast Reapers
Shroudguard
Chainguard
Total: 1970/2000
Command Points: 2
It's not the perfect list, but it's a good starting off point for you to play games and tweak as you see fit.
You're almost always going to want 30 Grimghast Reapers, even if you switch to playing Death or Legions of Nagash, so this is a solid investment.
The reason I've spec'd the Artefacts in this way, they can all now cap objectives that require a Wizard or Hero with an Artefact. Wychlight will help you get Spectral Tether off more reliably, and if you cast Temporal Relocation from the Mortality Glass onto the Chainrasp horde, you can get up to
3D6 from spell healing alone, plus depending on what you kill, D3 from the Spirit Torment and D3 from the Rule of the Spirit Hosts general trait.
The Lantern Guardian will babysit the big 40 Chainrasps, the Knight of Shrouds and Spirit Torment babysits the Bladegheists, and the Mortality Glass Guardian can babysit the Reapers. Because units have to be wholly within 12" of a hero to benefit from Restless Dead (and other buffs), you typically want at least one character for each main unit you bring.
You're going to find that as you play games, your playstyle will dictate what units you like to bring and how you play them.
For example, I play a very aggressive alpha-strike army, using a hammer to distract my opponents (typically the Revenants) while my characters and other units hop onto objectives, so this is the list I normally run, to give you an example:
