Nexus 5 (Unrooted) Restarts similarly to a Bootloop: What is the problem?

[AC Question]

Today was the first time I've had this issue with my Nexus 5, granted I've had it for almost 3 years now. When I turn on my phone (Which I believe is on 6.0.1), it goes into a bootloop only sometimes. On several occasions, it gets to the loading screen where there are moving colors about to transform into the word ''Android'', on much rarer occasions, it actually boots properly. Regardless of the progress it goes into actually booting, it eventually restarts and puts it back itself into a loop.

As of now, I can still access the bootloader and every functionality of it.

I was wondering if any of you had faced similar issues and knew if this was a hardware issue or a software issue.