If you have an Xresources file that looks like this:
! special
*.foreground: #dfdfaf
*.background: #1c1c1c
*.cursorColor: #dfdfaf
! black
*.color0: #1c1c1c
*.color8: #878787
! red
*.color1: #af5f5f
*.color9: #af5f5f
! green
*.color2: #87875f
*.color10: #87875f
! yellow
*.color3: #af875f
*.color11: #af875f
! blue
*.color4: #878787
*.color12: #878787
! magenta
*.color5: #af8787
*.color13: #af8787
! cyan
*.color6: #87afaf
*.color14: #87afaf
! white
*.color7: #dfdfaf
*.color15: #dfdfaf
then you can make a Tilix theme using the colours.
To do so do:
$ themix <Xresources theme> 'Theme name'
The theme name will be what comes up under the color tab of your profile. After that select the theme and you're good.