nxt_test: 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/nxt_test - from package: python-nxt

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

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