What is your growing medium? Doesn't look like nute burn, if anything it looks like a deficiency. Maybe a nitrogen or potassium deficiency, need more opinions though.
And fill everything out: REQUIRED INFORMATION FOR GROW SUPPORT
What Strain is it?
Is it Indica, Sativa or Hybrid? What percentages?
How Many Plants?
Is it in Vegetative or Flowering Stage?
If in Vegetative Stage... How Long?
If in Flowering Stage... How Long?
Indoor or Outdoor?
Soil or Hydro?
If Hydro, Reservoir size?
If Hydro, Reservoir Temperature?
If Hydro, what type of Medium?
If Hydro, what type of Setup?
If Soil... What is in your Mix?
If Soil... What Size Pot?
Size (Wattage) of Light? How Many?
Is it Air Cooled?
Temperature of Room/Cabinet?
RH of Room/Cabinet?
PH of Medium or Reservoir?
Any Pests?
How Often are you Watering?
Type and Strength of Fertilizers used?
Size or Square Footage of Room?
This information is necessary for accurate support to be given.