What is the equivalent of cold storage or paper wallet for NXT? I want to be able to secure my NXT in cold storage. What are some ways of doing this? 

Since NXT is only accessible via a brain wallet, I can just store the passphrase on a paper, but what if I wanted to see it as a watch-only address? Is that even possible?
It is possible, but quite more difficult than with Bitcoin.

All NXT tokens/coins are stored on the network, but it is possible to create an account "offline" that is secured by a 256-bit public key and does not expose your private key to the network.

There is a step-by-step tutorial on the NXT-Forum.