I won't get into the chain/line rode. Different cruising locations, different requirements.
What I will say is, with your new chain, take better care of it.
We have @ 150' of chain and 200' of 8plait behind it. Every winter I wash my chain. No not soap & water, I use anti-corrosive spray. The chain is spliced to the line so as I pull the chain from the locker and as I put it in a bucket I spray it with the anti-corrosive. I then let it sit for the winter.
In the spring I remove the chain, feed it back into the locker, attach it to the anchor swivel and I'm ready for another season. No rust or corrosion on the chain. IF I could figure out how to attach a picture I'd send you 1 of our rode, the chain on top of the line and all is happy.
IF you are talking of 3 strand nylon, you'll always have a hocking issue with the 3 strand twisting up.
BTW, chain is used as a weight, not necessarily just for rocks or coral. The more parallel to the bottom your anchor shank is the better it will hold. That is 1 reason some use a kellet to hold the rode to the bottom. So you might want to revisit your lack of chain in your rode makeup.
Good luck.