nvALT is not available for Linux but there are plenty of alternatives that runs on Linux with similar functionality. The best Linux alternative is Joplin. It's not free, so if you're looking for a free alternative, you could try Standard Notes or Google Keep. If that doesn't suit you, our users have ranked more than 100 alternatives to nvALT and many of them are available for Linux so hopefully you can find a suitable replacement. Other interesting Linux alternatives to nvALT are Obsidian (Free Personal), Typora (Free), CherryTree (Free, Open Source) and Zettlr (Free, Open Source).
Joplin is a free, open source note taking and to-do application, which can handle a large number of notes organised into notebooks. The notes are searchable, can be copied, tagged and modified either from the applications directly or from your own text editor.
Zettlr is a supercharged markdown editor that combines many writing editor features and collect them in one application. It aims at speeding up your workflow and help you write without any interruptions.