I’ve been trying to get crat nanos with click saver, but the missions seem to have to be pretty high for me to get them. I’m only 106 and really need the new charms and pets but can’t solo those missions, especially without being able to charm something in them.
How can I get them without grinding a bunch of levels with sup-par nanos, even while doing the 120+ missions or whatever it is for the nanos.
The most direct way is “blitzing”, see Blitzer Bert.
Various professions have various ways of getting through missions that are too high to complete. Remember, you don’t need to clear a RK mission to get the item reward. Try to get a mission that involves picking up an item, repairing something, or seeing someone rather than an assassination mission.
If you get a runspeed buff and HoT from a fixer, you can run very quickly through the mission, getting into and out of a room before the mobs can hit you. Anyone can do this with practice. This is blitzing in the literal sense.
As a crat, you also have access to calms. If you have high enough nanoskills, you can calm your way through the mission, looting chests and what-not, and getting your reward.
If you have very high concealment (e.g. agents), you could sneak through the mission. Probably doens’t apply to your crat, but keep it in mind for later. 
I hear people talking all the time about how easy it is to blitz. When I try, even with the best fixer buffs, I get killed repeatedly until I end up giving up and abandoning the missions. I just can’t seem to get the hang of it.
I think this may be exactly where many people take the wrong turn.
Its not the fixerbuffs that make you good at blitzing, its still about you, the player.
Srompu summed it up nicely, but allow me to stress out some points:
Even with GSF and HNQ your character will be put through a meat grinder if you do not know exactly how to complete your mission.
When running through all the available rooms, you’ll simply collect a comet trail of adds, some of which will take time to aim and hurt you or even snare/root you.
I consider it important to stop for a moment in the second room of a mission to get a good look at the layout.
With some experience its possible to get a good feel on where your mission objective is located (usually a large room as far away from the entrance as possible, or, on some notable exceptions, in a hidden room, so consult your PF map).
Especially in lower level missions it may be entirely possible to spot the mission objective right away.
A Find-Person-Target usually belongs to the same faction as your character and can be easily spotted on the PF map. Likewise a target for assassination will always belong to a different faction (duh) and may stick out of the normal dots on the map as well, may it be the single monster-dot or the single blue/orange dot in an mission otherwise inhabitated by white dots.
So, to sum it up, know where to go before you start!
Use an aggression enhancer to pull single targets out of a group without attracting social aggro.
Abuse line of sight as much as possible to avoid being spotted by the mobs.
A bureaucrat-related tip for blitzing: You have a pet. Make use of it!
Do not waltz into a room first, attracting everyone’s attention to yourself.
Your pet is selfcasted, weak and expendable.
It is nevertheless able to catch the attention of your targets for a few hits.
Make the pet attack an unconvenient target in your way. Let it punch the target a few times to get aggro while staying out of line of sight yourself to avoid aggro.
Now spring to action yourself and either calm or snare the mob.
Make the pet stop attacking when you cast so it does not break the calm/snare and to let its healdelta kick in.
Yes it may take three or four tries to land a calm on a nasty target, but your pet just bought you the time.
Rinse and repeat until you get to your mission objective.
Blitzing isn’t always easy. People say it’s easy because they’ve been playing the game for 10 years 
Experience + practice, practice, practice. You’ll get how it works soon enough!
Try to get missions at outposts next to whompa clusters - you can do that by rolling missions from the location you want to go to. lets say you want to go to city of homes - go to city of homes and roll missions and note where those mission send you and then go to those locations and roll missions to City of Homes. Also use the save terminal if one is near the mission entrance - that way you aren’t spending time returning to missions,
Pre-cast an extra pet shell before blitzing- that way when the pet dies in a blitz mission you can simply click the shell and have a replacement pet. Or you can terminate the pet and click the pet shell and have the pet right next to you again . Pet warp nano helps sometimes. Or try /pet behind or /pet wait in some instances. Again, experience dpoing this stuff helps. Map upgrades. The old white healing kits are handy - not the black/grey battle kits. Wear a piece or two of omni medsuit if doing so bumps you up to a higher QL stim.
Don’t roll Human missions - Human mobs will root and snare you. You want monsters in your missions. If you’re unsure how that works google " anarchy online mission settings 101".