I know you can change the batting order to bring in a nightwatchman but it would be nice to get a reminder to do it and perhaps make it a temporary thing so you don't forget to alter it when it isn't needed. Maybe in the general settings there could be an option for 'Nightwatchman alert' set to, for example: 5 overs, 10 overs and No (if you're Jonny Bairstow).
Then if you're batting with 5 overs left in the day you get a pop up saying 'Would you like to pick a Nightwatchman?' then you can push a button, scroll through your team and pick who you want it to be.