According to GamesRadar, Resident Evil 3 Remake's producer Peter Fabiano spoke to Official Xbox Magazine, describing how Resident Evil 2 Remake's Mr. X was a huge inspiration in designing Nemesis in Resident Evil 3 Remake.
The 188th issue of Official Xbox Magazine can be picked up now, and includes the interview where Fabiano states that Mr. X in Resident Evil 2 Remake turned out to be a lot scarier than expected and also set a higher bar for Nemesis in Resident Evil 3. Once Mr. X was created in RE2 Remake, the director stated that the team "Nemesis-ified" him. This led the team to take things much further, making the relentless pursuer feel like a real threat.
In addition to that, we also learned that safe rooms in Resident Evil 3 Remake are no longer safe. What we mean is that Nemesis can break through certain safe rooms. This should really help sell how scary Nemesis is.
If you haven't heard about safe rooms in Resident Evil 2, there were special rooms in the original game that allowed you to save your game at a typewriter and plan your next moves. However, this is no longer going to be the case in the RE3 remake. I can already imagine jumping off my chair when Nemesis breaches into a safe room when I try settling down my nerves.
I somehow feel that Nemesis will only breach through these safe rooms only when he is pursuing you, and you then choose to enter a safe room. Otherwise, these safe rooms should function as normal, like they did in the original game. Safe rooms actually gave you that brief break you need to collect yourself together before venturing out into the horror zones again.
Now if Nemesis is chasing you in Resident Evil 3, there is no way you can cheese him into a safe room, making the experience a lot more terrifying. You'll have to be more strategic in how you lose his interest and maybe utilize some stealth to evade the relentless pursuer.
With that being said, I can already speculate the number of memes and videos showcasing people screaming at top of their lungs when Nemesis breaches through the safe room walls to catch them (myself included).