The text and icons are small because your pixels are small. Or your pixels are the same size and you are farther away (TV, for instance). The portrait in the top right is 64 pixels wide. When monitors were 800x600, this was like 8% of your screen width, but now in 1920x1080 it is only 3%.
In your Resolution menu, there is a UI upscale that Doubles (or triples, or even quadruples) the UI elements, like text, portraits, windows, etc, by using twice the pixels (4 pixel square pretending to be 1 pixel). You can turn this on at your 1920x1080 resolution, but then the game will look like you are using a 960x540 resolution, which is not even as tall as the game's original 800x600 minimum size in 2002.
My advice is that you change the resolution of your monitor, from 1080p to 720;p, and then change your Windows scaling (you might have it turned up already to 120% or something if the NWN text is small for you) down, to keep Windows looking the same.
If you don't like this idea, running NWN in exclusive full screen (Alt + Enter) will allow you to set your own resolution for the game while you're playing it, but you will not be able to switch between programs (Alt + tab) easily, since this is the same as changing your Windows resolution, but automatically and temporarily.
Both of those methods will "Virtualize" a resolution, your monitor has individual pixels, of course, you aren't replacing them with bigger ones, they are permanent. This new smaller resolution will approximate the look of a smaller resolution just like the UI upscale does, but at the Operating System level, with your GPU, not NWN's UI engine.
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In your Resolution menu, there is a UI upscale that Doubles (or triples, or even quadruples) the UI elements, like text, portraits, windows, etc, by using twice the pixels (4 pixel square pretending to be 1 pixel). You can turn this on at your 1920x1080 resolution, but then the game will look like you are using a 960x540 resolution, which is not even as tall as the game's original 800x600 minimum size in 2002.
My advice is that you change the resolution of your monitor, from 1080p to 720;p, and then change your Windows scaling (you might have it turned up already to 120% or something if the NWN text is small for you) down, to keep Windows looking the same.
If you don't like this idea, running NWN in exclusive full screen (Alt + Enter) will allow you to set your own resolution for the game while you're playing it, but you will not be able to switch between programs (Alt + tab) easily, since this is the same as changing your Windows resolution, but automatically and temporarily.
Both of those methods will "Virtualize" a resolution, your monitor has individual pixels, of course, you aren't replacing them with bigger ones, they are permanent. This new smaller resolution will approximate the look of a smaller resolution just like the UI upscale does, but at the Operating System level, with your GPU, not NWN's UI engine.