Plenty of coaches run nutrition in a second app because the one bundled with their platform is awkward to use. That means a second subscription, a second login, and numbers that live apart from the training you are already reviewing. You can keep it in one place.
Set the target from what you already know
You do not need a lab. Mifflin-St Jeor gives a solid daily target from height, weight, age and activity. If you have a body-fat figure, Katch-McArdle uses lean mass instead and tends to fit leaner or heavier clients better. No body-fat number to hand? Three tape measurements give an estimate, and it should be labelled as an estimate everywhere it appears afterwards so nobody treats it as a scan.
PTToolBoxruns both formulas and picks based on what you have entered, so the target is grounded in the client's own numbers rather than a generic calculator.
Filter to what they can actually eat, first
The failure mode with meal plans is a plan that includes something the client is allergic to. Set a client's exclusions once, and every meal should be filtered against them before any meal is chosen, not checked afterwards. The exclusions then belong on every sheet the client receives, printed in the title, so the constraint travels with the plan instead of living only in your head.
Give them something they will actually use
A target is not a plan. What a client can follow is a one-page targets sheet sized to read on a phone, a recipe card for each meal, and a single shopping list totalled across the days so they buy once. On your name and colours, it looks like your coaching rather than a screenshot from an app.
Know when not to prescribe tracking
Not every client should be counting macros. A general-wellness client is better served by a target to aim at and a plan to follow than by a tracking habit that becomes its own source of stress. Save the strict numbers for body-composition and stage-prep clients who have signed up for that level of detail. Matching the structure to the client is the coaching; the tool just makes either version quick to produce.