Set to equal horizontal and vertical coordinates

ClearAll@f;

f[x_] := x Log[x]
Manipulate[Refresh[functions = Table[D[f[x], {x, n}], {n, 0, nMax, 1}];
  orders = 
   Table[D[f[x], {x, n}] // Inactivate // TraditionalForm // 
     ToString, {n, 0, nMax, 1}];
  labels = 
   MapThread[#1 <> " = " <> ToString[#2, TraditionalForm] &, {orders, 
     functions}];];
 Plot[functions, {x, 0, 5}, PlotLabels -> labels, ImageSize -> 700, 
  AspectRatio -> Automatic, 
  PlotLabel -> Row[{"f(x) = ", f[x]}]], {{nMax, 1, "Order"}, 1, 10, 1,
   PopupMenu}]

ClearAll@f;

f[x_] := Log[x]/-x^2
Manipulate[Refresh[functions = Table[D[f[x], {x, n}], {n, 0, nMax, 1}];
  orders = 
   Table[D[f[x], {x, n}] // Inactivate // TraditionalForm // 
     ToString, {n, 0, nMax, 1}];
  labels = 
   MapThread[#1 <> " = " <> ToString[#2, TraditionalForm] &, {orders, 
     functions}];];
 Plot[functions, {x, 0, 13}, PlotLabels -> labels, ImageSize -> 700, 
  AspectRatio -> 1, 
  PlotLabel -> Row[{"f(x) = ", f[x]}]], {{nMax, 1, "Order"}, 1, 10, 1,
   PopupMenu}]

The problem is that the functions depend inversely on x so they diverge as x -> 0. Try removing PlotRange -> All.