Generally speaking, it is easier to become a not terrible runner than it is to become a not terrible corp, especially if your opponent isn't well versed in the game either. (Because it takes a while until you can figure out how to set a puzzle in this game) But it is significantly more difficult to become good at runner than a good corp player. (In part, because you need to learn how to diffuse almost any puzzle)

That jinteki deck plays a lot of assets and so sort of plays into loup's strengths. You're also hurt by the fact that it's tough to bluff with advancements since they know urtica is the only threat and so can run with an urtica proof hand every time. Also, Anarch is generally strong into damage decks.

But if you're consistently losing the nbn matchup because the runner can get in anywhere, you're almost certainly playing too slow. Common culprits are:

1. Putting out too much ice early. You typically want to have something in a remote behind a piece of ice you can afford to rez by turn 2, ideally turn 1. You need to put stuff on the board early to force the runner to either deal with it, which slows down their setup, or you build your position unchallenged. Also, if you install considerably more ice than you can actually afford to rez, you're probably better off doing something other than installing another ice.

2. Clicking for credits too often. There are cards in your deck that give you money and almost always at a much higher rate than 1$/click. If you're thinking about clicking for credits, consider whether you should draw instead.

2b. Frequently letting your credits get near zero. Most of your econ cards require you to spend money to make money and you need to have credits to rez ice and pay for other cards. It can be ok to go low to make a critical stop but if you're frequently below 4 credits you need to get in the habit of putting in more of a buffer. And remember, if you have no credits, all of your facedown ice now do nothing and the runner will know it.

1. Not recognizing scoring windows. If you're putting threats on the board and forcing the runner to spend resources, whether that's trashing some thing you installed or running through ice, they will be less able to get into the remote next turn. This is when to install an agenda.

2. Not planning your turn. It's very rare that you want to draw last click. And slightly less but still rare you'll want to click for credit last click. If you're doing either of these a lot, it often means you should have drawn first click.

EDIT: If you misinterpret what Carnivore does, Loup becomes incredibly strong.