Yes — a couple of options:
AT+CEREG? — when subscribed at level 2 or higher (AT+CEREG=2), the response includes <AcT> as the last field:
7 → E-UTRAN (LTE-M)9 → E-UTRAN NB-S1 (NB-IoT)
Example:
AT+CEREG?
+CEREG: 2,1,"002F","0012BEEF",7
That trailing 7 means you’re connected on LTE-M.
AT%XMONITOR — gives the full picture (registration status, AcT, band, RSRP, RSRQ, operator, cell ID, etc.) in one shot. The <AcT> field uses the same 7 / 9 encoding.
Note that AT%XSYSTEMMODE? only tells you what’s enabled and preferred, not what’s currently active — so for “what am I connected on right now”, use +CEREG? or %XMONITOR.
I referenced the AT commands from Nordic:
Download: https://docs-be.nordicsemi.com/bundle/ref_at_commands_nrf91x1/attach/nrf91x1_cellular_at_commands_v1.4.pdf?_LANG=enus
URL: https://docs.nordicsemi.com/bundle/ref_at_commands_nrf91x1/page/REF/at_commands/intro_nrf91x1.html
