The money, and which coin to use

Nexus takes two coins. They are not equal on privacy, and privacy is the reason you are on Tor, so this choice is worth a minute.

You can pay on Nexus in Bitcoin or Monero. The market is happy with either. Your own privacy is not, and that is the lens to choose through.

Why Bitcoin is not the quiet option

Every Bitcoin payment is written to a public ledger that anyone can read and that never forgets. The sending address, the receiving address and the amount all sit there permanently, and there is a whole industry built on tracing those records back to real people. Bitcoin is fine if you already hold some and you understand that the payment itself is not private. It is the wrong default for anything you want kept to yourself.

Why Monero is

Monero hides the sender, the receiver and the amount by default, built into the protocol with no switch to forget. There is no public trail to walk backward because the network never records one. For the kind of purchase that brings most people to a market like this, Monero is simply the right coin, and Nexus treats it as the first one.

Funding without a thread back to you

Whichever coin you use, do not send it straight from an identity-checked exchange into the market. Move it into a wallet you control first, let it arrive, and pay from there. For Monero, Feather on a desktop or Cake Wallet on a phone are both easy and both can route over Tor. Buy a little more than the order needs to cover network fees, and keep only what you are about to spend on the market.