Yes there are many limitations.
You cannot design a huge full site form that runs on a 3 GHZ processor with 16 GIG of RAM and a 2GHZ RAM video card and expect it to perform the same as a mobile device runinng an ARM processor and 512MB RAM.
Some controls are not compatible for example the Managed MetaData control, Page Viewer control and Button control.
Some Runtime functions such as lookup() and UserProfileLookup() do not work.
Any images will need to be web facing with no authentication required.
Tabbed Forms do not work.
We have many companies using the app out in the field and it meets their needs but I suggest testing your scenarios to see if they can be acheived on the Mobile app.
There are some advantages to Nintex Mobile App that the full site does not have like Offline form submission and deeplinking capabilities.
Hi,
The Help files for Nintex forms advise which controls are not compatible with Nintex Mobile.
https://help.nintex.com/en-US/nintex2019/current/#sp2019/Forms/Controls/Controls.htm%3FTocPath%3DWork%2520with%2520the%2520basics%7CActions%2520and%2520controls%7CForms%2520controls%7C_____0Click on a control and if its not compatible you will see the message : This feature is not supported in Nintex Mobile.