Since this explorer is database-free, it doesn't natively support address balances & transaction history. However, you can check it in :
https://explorer.nusacoin.org/address/nu1qc3g73uvu36df8fl2z4galwptsucx36rw6upmpk{
"isvalid": true,
"address": "nu1qc3g73uvu36df8fl2z4galwptsucx36rw6upmpk",
"scriptPubKey": "0014c451e8f19c8e9a93a7ea1551dfb82b873068e86e",
"isscript": false,
"iswitness": true,
"witness_version": 0,
"witness_program": "c451e8f19c8e9a93a7ea1551dfb82b873068e86e"
}