documentclass{article}
usepackage[utf8]{inputenc}
usepackage[T1]{fontenc}
usepackage[polish]{babel}
usepackage{listings}
usepackage{color}
definecolor{darkgreen}{rgb}{0,0.5,0}
definecolor{darkviolet}{RGB}{138,43,226}

lstset{
  morestring=[s]{"}{"},
  morecomment=[s]{?}{?},
  morecomment=[s]{!--}{--},
  commentstyle=color{darkgreen},
  moredelim=[s][color{black}]{>}{<},
  moredelim=[s][color{red}]{ }{=},
  stringstyle=color{darkviolet},
  identifierstyle=color{blue},
  basicstyle=ttfamily,
  columns=fullflexible,
  showstringspaces=false,
  commentstyle=color{gray}upshape,
      literate={ą}{{k{a}}}1
             {Ą}{{k{A}}}1
             {ę}{{k{e}}}1
             {Ę}{{k{E}}}1
             {ó}{{'o}}1
             {Ó}{{'O}}1
             {ś}{{'s}}1
             {Ś}{{'S}}1
             {ł}{{l{}}}1
             {Ł}{{L{}}}1
             {ż}{{.z}}1
             {Ż}{{.Z}}1
             {ź}{{'z}}1
             {Ź}{{'Z}}1
             {ć}{{'c}}1
             {Ć}{{'C}}1
             {ń}{{'n}}1
             {Ń}{{'N}}1
}

begin{document}

begin{lstlisting}
    <nazwa_elementuóśóóśóóśó nazwa_atrybutźćóźvxcóu="wartośćóóźłćóżć">
        zawartość elementu
    </nazwa_elementu>
end{lstlisting}


end{document}