After reading several good writeups in this forum about how to get steam and NS running I still ran into a few issues with it. Here are details on how I got these errors solved.
1. Fix max ex_maxerrordistance errors and "reliable channel overflow" client crashes: -create userconfig.cfg in half-life\ns and add alias "ex_maxerrordistance" "" <make sure your \ns\config.cfg file contains exec userconfig.cfg>
2. -Fix cmdr menu font, console message RE missing fonts and make them less fuzzy: <This improves the marine right click cmd menu some but not all the way,> -backup and remove all files from half-life\ns\gfx\vgui\fonts and -backup and remove all ****_textscheme.txt from half-life\ns note: there have since been reported several other ways to edit the _textscheme.txt files and change the res on fonts, this seems to work for some, but this method fixed the most for me.
3. Fix missing sprite errors which cause comm fps lag and console error msgs: -copy half-life\ns\sprites\blank.spr to half-life\ns\sprites\techtree\tech0s.spr -copy this same file to each of the following in the half-life\ns\sprites dir: top_left.spr top.spr top_right.spr left.spr right.spr bottom_left.spr bottom_right.spr horizontal.spr vertical.spr top_left2.spr top2.spr top_right2.spr left2.spr right2.spr ch_sniper.spr bottom.spr commander.spr
These changes worked for me at 1024res so YMMV. Backup everything you change and see if these changes don't help your console get closer error free and your steam NS game less laggy.
EDIT: Pls read my below post RE: the splash screen. Download the resource.zip to get the NS splash screen in steam