You can't explicitly change the sizes of those module icons in NetBeans, but it can be done implicitly by increasing the size of the font used by the NetBeans IDE.
That font size is unrelated to the font size used for displaying your source code; instead it is used for rendering IDE text such as labels on tabs ("Files", "Services", etc.), menu entries and file names within panels such as the Projects tab. When the font size of a file name is changed, NetBeans also makes a corresponding increase or decrease to the size of the icon (e.g. the module icon) to its immediate left.
To modify the font size used by NetBeans specify the fontsize parameter when starting NetBeans. For example, to get NetBeans to use 18 point font (not recommended!) on Windows 10 I made this call:
C:NetBeans82_151in
etbeans64.exe --fontsize 18
The second screen shot below shows that using 18 point font also increased the size of the icons:
I deliberately used a significantly larger font to clarify the effect of the change in the screen shots, and the overall result was ugly. But for your purposes perhaps a smaller increase in font size will help you with the size of the icons.
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