My .Xdefaults has the following settings, which seem to have gotten me
back to something close to what xterm used to do.
nxterm*saveLines: 2000
nxterm*background: Black
nxterm*foreground: white
nxterm*reverseVideo: false
nxterm*scrollBar: true
nxterm*saveLines: 2000
nxterm*reverseWrap: true
nxterm*font: fixed
nxterm*fullCursor: true
nxterm*scrollTtyOutput: off
nxterm*scrollKey: on
nxterm*VT100.Translations: #override\n\
When I try
nxterm*geometry: 80x50
the popup menus for Control-mousekey are badly mangled,
so I'm living with the default 80x24 initial screen size for now,
using the mouse to resize the windows to something more reasonable.