nfc-mfclassic: command not found

Maybe Your $PATH variable doesn't contain the default paths? echo $PATH should give something like:

[root@server ~]# echo $PATH
/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin

If it's empty, You may set the PATH variable with this command

export PATH="/usr/local/sbin:/usr/local/bin:/sbin:/bin:/usr/sbin:/usr/bin:/root/bin"

On Debian possible default full paths are:

/usr/bin/nfc-mfclassic - from package: libnfc-bin

You may install the required package with command apt-get install {package}

Error in other languages:
nfc-mfclassic: bevel nie gevind nie
nfc-mfclassic: comandă negăsită
nfc-mfclassic: comando não encontrado
nfc-mfclassic: commande introuvable
nfc-mfclassic: command not found
nfc-mfclassic: käsku ei ole
nfc-mfclassic: không tìm thấy lệnh
nfc-mfclassic: komanda nerasta
nfc-mfclassic: Kommando nicht gefunden.
nfc-mfclassic: kommandot finns inte
nfc-mfclassic: komut yok
nfc-mfclassic: nie znaleziono polecenia
nfc-mfclassic: níor aimsíodh an t-ordú
nfc-mfclassic: no se encontró la orden
nfc-mfclassic: no s'ha trobat l'ordre
nfc-mfclassic: opdracht niet gevonden
nfc-mfclassic: parancs nem található
nfc-mfclassic: perintah tidak ditemukan
nfc-mfclassic: príkaz nenájdený
nfc-mfclassic: příkaz nenalezen
nfc-mfclassic: команда не найдена
nfc-mfclassic: командата не е открита
nfc-mfclassic: 命令找不到
nfc-mfclassic: コマンドが見つかりません