Transferring pension from Nest to new workplace pension

Hi all. I wonder if you can help. I was signed up to Nest with a previous employer, i was enrolled for about 7 years. I've got about 30k in that pension. I've moved to a new employer who use Smart pension. I'm just wondering if i should move my Nest pension into the new one or just leave it alone. I'm wondering if charges will just reduce it down to nothing if i leave it. I'm not sure how they work. I won't be paying any more into the nest one. Thanks in advance for any responses. I'm 44 and i suppose i'll try to stop working at about 65.