Catch up with nurse: hospital tackling chaos, mostly (6)
I believe the answer is:
enmesh
'catch up' is the definition.
(I've seen this in another clue)
'nurse hospital tackling chaos mostly' is the wordplay.
'nurse' becomes 'en' (abbreviation for enrolled nurse).
'hospital' becomes 'h' (abbreviation for hospital on maps).
'tackling' means one lot of letters goes inside another (to tackle is to take possession of).
'chaos' becomes 'mess' (I've seen this before).
'mostly' means to remove the last letter.
'en'+'h'='enh'
'mess' with its final letter removed is 'mes'.
'enh' placed around 'mes' is 'ENMESH'.
'with' is the link.
(Other definitions for enmesh that I've seen before include "Entangle as in net" , "Men she changed to entangle" , "snare" , "trap" , "Tangle up in a net" .)