Hi and welcome!
Follower alignment is usually 1 step alignment variance from the deity's alignment because of this, the deity system generally allows for the 1 alignment variance. That means that if your deity is chaotic evil, it allows for chaotic evil, neutral evil & chaotic neutral followers usually. The follower alignments of the gods should be listed on the deity page, and if you encounter any issues with it, you can ask any DM in game for some help. As long as your character fulfills this alignment criteria, then you're quite safe to pray for a blessing & to play as a cleric.
Also, note that both of your cleric domains must be domains the deity allows. Continuing to use Cyric as an example, you can have 2 of the Chaos, Destruction, Evil, Hatred, Illusion or Trickery domains, but you couldn't take travel domain & Chaos for instance. This got changed a few years back for balance reasons and unless I'm mistaken or mis-remembering and it got changed back to only needing 1 domain of your god, this is a somewhat important part of the deity system/cleric domain system. This means that if you dont have 2 domains of your gods portfolio then you recieve a fallen token, which indicates that your character is fallen and this bars access to cleric abilities, such as spells.
However this 2 deity domain restriction usually shouldn't be a big problem for playing a cleric of any god, as the domains have generally been given a power bump to make them all stand on an equal footing. These additions are posted
here under the domain listing. The bonus powers given based on domains that is listed on the Deity system page are only applied when you pray, the changes listed in the link I put in are permanent additions to the domain. For instance, the evil domain on Amia gains all the standard bonuses + Energy Drain at level 8 to the clerics spellbook. (The other spells listed in the Evil domain come with the domain in vanilla NWN)
As for paladins, paladins are always Lawful Good, because of this they usually have to follow gods that are either Neutral good, lawful good or lawful neutral. I say usually because we allow for some wiggle room as some deities do have paladin orders, while not being within the 1 step alignment spectrum. One example of this is the Guardians of Light order, which are an order of paladins dedicated to Selune, which is a chaotic good deity. Because she has a known paladin order that is established in lore, the 1 step alignment restriction is voided in this case. However it is strongly recommended for paladins to stick to deities that fall within the 1 step alignment spectrum, meaning neutral good, lawful good or lawful neutral deities. This is because following a chaotic deity can offer some difficulties for a paladin as they are bound to law & order, which tends to conflict with chaos in the same way good & evil can. (However it can also provide you with some unique RP opportunities, so it's players choice here really.) While some Chaotic good deities have paladin orders, paladins cannot follow evil deities for obvious reasons.
Hope that clears it up!