Let us start off with comparing this to Dyson Mem Chip. Both these cards give you 1 and 1. This means you are spending 5 on Security Nexus's ability.
Pros
Bypass ICE. If you can beat a strength 5 trace, you can get past whichever one piece of ICE you want. Being Sunny Lebeau: Security Specialist and running this card gives you at least 3. So you have to pay at most two more than the Corp to bypass the ICE.
Immune to nasty ICE effects. If you hit an unexcepted piece of ICE or are running through Jak Sinclair's ability, you either bypass the ICE or end the run and take a tag. This can turn hitting a Janus 1.0 on a Jak Sinclair run into any other runner facechecking a Datapike. This is because even if the Corp boosts the trace and wins, you will take a tag and immediately end the run - no subroutines fire. All you do is spend your first actual click and 2 to remove the tag.
Cons
Expensive. You want to get this out as early as possible to use it as much as you can. However, 8 early game will set you back 2 to 3 turns. Considering Sunny Lebeau: Security Specialist has expensive breakers as well, it can give the Corp too big of a window to score.
Caprice Nisei. You can bypass a piece of ICE but if you lose the psi game, you will have to get past the ICE the old-fashioned way. But then again, which runner is not affected by this line of play by the Corp.
Surveillance Sweep. If you are forced to pay for the trace first then the Corp is paying a minimum amount to end the run and give you a tag.
Synergies
Jak Sinclair. Since Security Nexus is not a program, you can still use it to bypass an ICE on a Jak Sinclair run.
High . If you can add even more link then you are only going to increase Security Nexus's power. Rabbit Hole and Access to Globalsec are common ways to do this.
Power Tap. By itself this card may as well just be another link because getting one credit for the trace and pay one extra is the same as paying one less to begin with. However, if you are boosting your base link or "would be doing it anyway" then you are getting ahead economically. Power Tap can then be turned into more drip econ as you can guarantee a trace each turn with Security Nexus. And it only gets better whenever the Corp has cards to initiate a trace.
Conclusion
This console has an undeniably powerful ability. And once on the board, can make most servers penetrable. The tempo hit that you will take from installing this will give a big scoring window to the Corp. Against glacier style decks like typical Haas-Bioroid: Engineering the Future, Blue Sun: Powering the Future and Jinteki: Replicating Perfection this is not as big of a deal as you are both playing a long game and will most likely benefit you the most in the long run.
However, against fast advance decks, this tempo hit very well may give the Corp a chance to score their first AstroScript Pilot Program. After this, they are not going to be playing their agendas in remote servers, they will be scoring them out of hand so bypassing ICE is not as big of a deal. Also, kill decks which rely on being ahead economy-wise will take advantage of your low credit pool after this install by putting agendas in open remotes for you to either steal or them to score. With the former you might be hit with a Midseason Replacements or a SEA Source and subsequent meat damage. The latter meaning they can just score 7 agenda points for the win.
This card seems to make your more favourable matchups better but your unfavourable matchups worse. This card will not be a typical include in tier 1 decks while fast advance and kill decks are in the top tier for Corp decks.